Issue:
5 Blank (date only) errors in console, game will not run.
I was able to reproduce this bug in both Unity 2019.1.5f1 and 2019.3.0a4
I submitted a bug report but I figure it might help someone to see the temporary fix I did.
We read through the Editor Log and found this:
No usable version of the libssl was found
/home/abezuska/Unity/Hub/Editor/2019.1.5f1/Editor/Data/Tools/RoslynScripts/unity_csc.sh: line 64: 28227 Aborted (core dumped) "/home/abezuska/Unity/Hub/Editor/2019.1.5f1/Editor/Data/Tools/RoslynScripts/../../Tools/Roslyn/csc" /shared /noconfig @ /UnityTempFile-c8355884da1220cdd9d43fb9e8e24eb0
Apparently Ubuntu 19.04 uses libssl1.1 and .net requires libssl1.0
THE FIX
Installing libssl1.0 from this source fixed the issue for me:
https://packages.ubuntu.com/xenial/amd64/libssl1.0.0/download