Unity .net 4.x errors without text?

Question

Game development

When switching to .net 4.x, there are 4 errors without text. unity version 2018.3.4f1
tell me how to fix it.

Answer 1

Read the logs:
https://docs.unity3d.com/Manual/LogFiles.html

C:\Users\<username>\AppData\Local\Unity\Editor\Editor.log