WebGL: "both async and sync fetching of the wasm failed". Build and runs works, fails when uploading

Hello,
I tried to build the most simple WebGL application possible with Unity 2020.1 as I was having issue with uploading my game. I thought it was the game itself so I tried a very simple project.

One label showing "Test"

While build and run works flawlessly locally, I tried to upload it on my ftp and get a few errors.
"Both async and sync fetching of the wasm failed"

Then the loading is stuck at 90%
I have the same behavior in Firefox and Chrome.
See errors here:
www.awakendreamsprod.com

Hope you can help, thanks in advance!

 

enabling Decompression fallback fixed my issue.. Now I'm not sure it's a good thing...
I have no experience with online application.
Should I do something else?
Thanks

 

I got the same issue where a simple application stopped at 90%.
Disabled the compression in Player settings - Publishing settings - Compression format and then it worked. At least in MS Edge.

 

I'm having the same issue as the original post. I have disabled compression and I still get the same error. Any other ideas?

 

yeah, same probleme here...

 

There is one bug where if you use "Filenames as hashes" together with a compressed build (gzip or brotli) then decompression will fail. Even with the new web.config or htaccess file.
This is due to the fact that when filenames are converted to hashes they lose their .data and .wasm extension in the naming.
Which brings me to my next point, they changed the extension a little bit. So mimetypes have to be changed accordingly.

If you're running old configurations you're going to require a new configuration.
https://docs.unity3d.com/2020.1/Documentation/Manual/webgl-server-configuration-code-samples.html

So yeah quite some changes have been made to 2020.1 WebGL, including the Template it uses. Old custom templates will be broken as far as I know.

WebGL Mobile is no longer blocked by an unsupported message. But it is not the most performant either.
for Apple devices, Safari is only supporting WebGL 1.0 (unless experimental WebGL 2.0 is enabled. They never continued development because they are focussing on WebGPU instead)
for Android WebGL 2.0 can be used on Chrome / Firefox. But still, not super performant.
The hope is that in some time (1 or 2 yrs) WebGPU is fully developed and embraced by all browsers.

 

It worked for me.

I'm using Unity 2020, and since that has a compression bug, I had to turn off GZip compression in the player settings (So go to File > Build Settings > Player Settings > Player > Publish Settings > set Compression Format to Disabled.

I assume when the bug gets fixed the Gzip can be turned back on. Then, following the link from Masked Mouse above, I went there, found the IIS Uncompressed section, and copied and pasted all of that text to a new Text Edit file (I work on a Mac, but not posting to Apache server in my case). Here is the link to the discussion about the bug > https://forum.unity.com/threads/unc...htmlscriptelement-script-onload-webgl.803967/

I saved the file, naming it web.config and then copied that up to my server into my build folder. When I reloaded the page, it worked.

 

To anyone following this- after chasing my tail on this exact issue for a week and doing what everyone mentioned above (as well as a few other things.) Here is the apache config that actually worked for me:

Code (Apache):

1. <IfModule mod_mime.c>
2. AddType application/wasm .wasm
3. AddOutputFilterByType DEFLATE application/wasm
4. </IfModule>

If you have turned off compression to work around the bug and have the line "AddEncoding br .wasm" in your config, it will throw the wasm error in any browser that isnt Firefox.

 

How do you find and copy the edited text file to the server? I have my .config file I made from the link, but how do I use/apply it to the build? Thanks

 

I don't know what is an apache config. Where should I put this code?

 

I'd also like to know where to put this code.

Been having the issue with my current project. I've tried all compression formats, hashes and no, development and release builds, I've tweaked the eneable exceptions and webassembly arithmetic exceptions settings, I've tried everything.

My game sometimes runs the first time from my disk but won't run a second time. It won't run even once if I post it online.

MY WORKAROUND:
This might not work for everyone but I did get a stable build doing it this way.
First of all, I used Unity's Cloud Build service. Building locally didn't work, but on Cloud did.
Default player settings didn't work even on Cloud. I'm not sure which of these was relevant, but these settings combined worked:
Enable Exceptions: None
WebAssembly Arithmetic Exceptions: Ignore
Compression Format: Brotli
Name Files as Hashes: false
Data Caching: True
Debug Symbols: false
Decompression Fallback: true

 

Any way we can add to your "vocalisation" about this? I wholeheartedly agree with everything you said about the decompression fallback, it shouldn't be an option, much less activated by default.

 

Sometimes just for tests I run builds on local servers with no configuration, so I do like this feature, but when on the actual production server, removing this code would be better.

 

I'm building a WebGL game, that's hosted on an AWS bucket. The only way I can get it to load from there is if I enable "Decompression Fallback".

From what I understand from this thread is that I shouldn't enable it but I can't get it to work without it.
Any advice on what I should do?

 

I have same issue too...
I change compression disable but still not working...

 

While I agree with the concept, Decompression Fallback was the only way for my client to get his WebGL game downloaded. Yes, it's a server configuration problem, but I haven't been able to find a solution anywhere. I dare say it's a trivial matter of updating the Content-Encoding and Content-Type on the server, but my client has access to a CPanel admin page, which looks to be allowing new content types to be added, but no matter what combination of entries he makes, he can't seem to get the compression working. And of course, then that falls back on to me, rightly or wrongly, and I'm now having to try and figure out how to get something that should be simple, working. He thinks it should "just work", and I don't blame him.

So, after all of that, is there any recommendations/instructions for the configuration of a system that has CPanel?

 

anyone found a decent solution? i only get this error when my game is opened through facebooks browser. funny thing is that its only on this game in particular event though it loads on desktop and mobile browsers. i dont know what to do!!!

in case someone might help this one http://todiktamo.slaga-games.com/ doesnt open through fb browser

and http://showcase.slaga-games.com/ works just fine. both use 2020.1.4f same build settings. im losing my mind. i tried some other builds that i had already given to clients and they worked fine in their hosting services but when i upload them on mine they dont work

 

Just want to bump the thread: I tried to build a demo for WebGL with both 2019.4 and 2020.2: 2020.2 fails and raises this error no matter what I try, and 2019.4 is working no problem: this has to do with a bug in the new version

 

It depends on your settings and server configuration.

The only bug so far which I am aware of and I don't know if it is already fixed or not is the toggle for "Name Files As Hashes" setting.
If toggled on it doesn't keep the required extensions in its name. The server can't serve the files properly when that happens.

So a few questions:
- Decompression Fallback turned off?
- What is your web server based on? IIS, Apache? else? unknown?
if IIS or Apache
- Do you use the server configuration file meant for either of those?
- Are you using Gzip or Brotli compression?
If Brotli
- Are you using https?

 

Tried all the build options, Decompression turned on or off.
No server, just the "build and run"
tries gzip brotli or none
https, yes

 

To anyone seeking a solution from this thread: I was having the same issue that people here are facing and couldn't determine what it was for 2 days. Finally I found out that when my game scene was loaded, the application froze or ran out of memory or something similar because I was instantiating so many gameobjects at once.

I solved my problem by adding a small timer after the scene was loaded before instantiating my gameobjects. Not sure why that makes such a difference, but it does and now my application works flawlessly.

Sorry if this post wasn't as technical as the other more informative ones, just thought I'd share my solution here if anyone else came across this similar issue.

 

Hi, apparently I have the same problem as Mikyjax, but my one DOESN'T EVEN LOAD. Please don't be too technical. I didn't understand a word of what was above, if you have a solution, can you please describe it STEP BY STEP please? Help is greatly appreciated.

 

I just ran into the same problem:

The project was created in Unity 2020.1 and updated to 2020.2.2f1 yesterday.
It's a pretty simple thing: A player that can walk around inside a room (2 objects: 1. floor+walls, 2. roof) and enter one of 2 doors. Each door is a plane with a lava shader (free asset from the store) on top (to make it "wobbly") and I also added bloom (to make it glow) through post processing.
This works fine in Unity itself but when I try to run the .html file in my browser (tested with Firefox 85.0 and Chrome), it displays a grey rectangle with the Unity logo and a loading bar but also pretty much instantly pops up the error message.

Compression was set to "Gzip" and if I disable it, there's an additional error message (it doesn't show up with compression enabled!), even though it still finishes exporting:

I already had problems with similar errors after updating yesterday but then I updated a couple of "Unity Registry" assets (everything installed is now up to date, PostProcessing: 3.0.1) and the errors were gone.

I keep reading about setting up a server but the "UnityWebRequest" code in my project is currently commented out, so I just double-click the html file or drag it into the browser of my choice. Am I missing anything here?

 

I wasn't sure if just double-clicking the html file was the right way to do it, so I googled a bit and just came across this video:
It tells you to use Firefox and change the "privacy.file_unique_origin" setting in its "about:config" to "false" (should be enabled by default).
I did that and all of a sudden my app is loading just fine (export with compression enabled), no error popup and also no error in the development console.

I enabled the setting again and all of a sudden the error was back. I never got the "browser not supporting WebGL" error shown in the video though.

Privacy mode isn't active but data caching is enabled.

 

Thanks for the warning. I'm aware, I'm going to change it back to "true" when I'm done testing.

It's interesting that this seemed to instantly fix it but I'm not sure if there's still a problem (that's just being ignored because of the setting) because I never got the proper WebGL error message shown in the video.
It would be interesting to see the full error message others got and if theirs has the "file://" part too.

Ad your server suggestion:
Download the file (right-click on "raw" - save target as), then cd to where it is and use this:

Or is there more to it?

 

I just noticed, emrun is already part of the WebGL package in Unity. For me it's in:
C:\Program Files\Unity\Hub\Editor\2020.2.2f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\Emscripten

As someone else already pointed out here, the full command is (if you let python add itself to PATH):

I installed the 64bit version but it complained:

I then also installed the 32bit version but still get the same error. Is "pywin32" something else?

Edit: I also tested what was suggested in the next post (here):

With "<old_WebGL_output_dir>" being the path to the index.html. It says

but doesn't open the file. When I open it myself, I get the "abort(...)" error again.

 

Thanks, I installed it and ran it again:

I re-downloaded the emrun.py today but it always outputs:

 

Changing those privacy settings for this purpose is not a good thing.
If you have issues with the "Build and Run" option of Unity, or you want to open your build without using the "Build and Run" button, you can use local web server.
One option is NGINX.
Another option would be Node.JS and the "http-server" package https://www.npmjs.com/package/http-server

 

@jukka_j
Thanks so much for the insanely fast fix!
Now it opens the browser and the error's gone too (even with the setting enabled).

 

I'm having the same issue when i run the HTML file directly, but im trying to upload my build to itch.io, and itch doesn't even seem to recognize the build as webgl

 

aight it turns out it was me being stupid, not itch. i just forgot to tell itch that it was an HTML game and not a downloadable

 

What apache config file? where is it found?

reading the response in the thread i feel like a real dumbass even though i've been working in unity for 7 years. I can't find an apcahe config file anywhere. can someone please help?

 

yes, i am using Apache. i managed to find the file. adding said code to it crashes the server.

is there a way to get live help? I am on a deadline. my game works perfecly in unity. Pc build works fine. but i dont know what's wrong with the web build. tried 20+ different things

 

My webgl build works fine in Chrome and Edge but not in Firefox: "both async and sync fetching of the wasm failed".
I use brotli compression without decompression fallback.
Is this a known issue in Firefox? Is there any solution?

In every browser I get the message: falling back to ArrayBuffer instantiation and Incorrect response MIME type. Expected 'application/wasm'.

This is the .htaccess:
<IfModule mod_mime.c>
# The following lines are required for builds without decompression fallback, compressed with Brotli
RemoveType .br
RemoveLanguage .br
AddEncoding br .br
AddType application/octet-stream .data.br
AddType application/wasm .wasm.br
AddType application/javascript .js.br
AddType application/octet-stream .symbols.json.br

 

So I was having this issue and making a web.config file in my server at the same level as the index fixed the issues.
https://docs.unity3d.com/Manual/webgl-server-configuration-code-samples.html

 

completely delete unity and reinstall it

 

Wow, there's a new one for Apache. They add:
AddType application/wasm .wasm.
and that fixed it!

 

I got this problem. And i turn on Compression format to Gzip, turn off data checking and decompression fallback solve it.

 

i check the structure of my website/server folder and found that my "GAME.DATA" & "GAME.WASM" are outside of the directory i.e. root...
Then I copy back them both to the Build Folder and game works like charge.....

 

After trying everything.Finally work for me , by following below step

1.Unity -> Player Setting -> Publish Setting -> Compression Format -> Disable
2.Unity -> Player Setting -> Publish Setting -> Decompression Callback -> On
3.After making build , go to the build folder
create two file
1. .htaccess - copy code from here -> https://docs.unity3d.com/Manual/webgl-server-configuration-code-samples.html
2 web.config - copy code from here -> https://docs.unity3d.com/Manual/webgl-server-configuration-code-samples.html

error disappear