OAuth2 login is not setup properly error

[batuakin 0]

Hello. I have migrated my project from V11 to V12.
 Everything works fine in V11. Everything works fine in V12, 
but the form and button where I downloaded the license file are exactly the same, and although they perform the same functions, I can send a request to my backend service without any problems in V11, but I get the error OAuth login is not setup properly in V12.
 What could be the problem? Can you help me?