Errors when I'm trying to import a project from Unity 2018 to 2019.

Hello. I suddenly started having errors when trying to test the game I was building in Unity 2018 (I don't know why it even downloaded that because I've installed Unity from the website last month). It wrote
Curl error 51: Cert verify failed: UNITYTLS_X509VERIFY_FLAG_EXPIRED, which then also shut Unity down, and it was said to be resolved by people when they updated their Unity version.

So I installed the latest Unity 2019, but when I try to import the project it keeps giving errors. At first it wrote something else, and while I didn't make any use of it I thought perhaps because I didn't also add the WebGL Module which was in my Unity 2018 installation it made issues, so I added that as well and currently it writes:

"An error occured while resolving packages:
One or more packages could not be added to the local file system:
.com.unity.ads: EPERM: operation not permitted, lstat
'C:\Users\user\AppData\Local\Unity\cache\packages\packages.unity.com\.tmp5448b91ZsjLQt02P\extract\Plugins\iOS\UnityAds.framework\UnityAds'

A re-import of the project may be required to fix the issue or a manual modification of ...manifest.json file.

Click on Retry to relaunch Unity and reopen your project.

Click on Continue to launch Unity. Some or all packages may not be imported which may cause compilation issues."

What is this issue and how can I fix it? Thanks in advance.

 

I've already fixed it. First, it seems to have kept looking for iOS ads even though it didn't use the iOS package earlier, but I added that as well, and second I think there was an issue at the time with the Unity servers and using your software apparently requires being connected to the servers.