WebGL Build has black square not present on other builds?

I have been at this single issue for a few days and have tried dozens of solutions from camera replacement and swapping every setting possible one by one on the build settings, to all the solutions suggested by the first few pages of google results.

Is there a way to deal with the black square as shown in the screenshot?

 

I solved the issue and wanted to let people know in case they get here from Google. I had a pretty unique scenario where the WebGL build was dying on a reference to a DLL partways through a function that was building textures. So in all the other builds, the script would create the big texture, do math, then move it and size it. On WebGL, it would hit an exception while doing the math, so it would never get to the moving and sizing part of the script. That left me with just a big black texture on screen.