Hello Kashif J.,
I'm the direct client Alexis is talking about !
I tried again to establish the admin consent but once again, even after waiting a day, i'm still having the same error message : {"type":"BadRequest","message":"Could not generate OAuth code and state","details":{}}
I tried on two separate Clay accounts, but i always get the same error message, so it may come from the Microsoft account. I looked everywhere and nothing is blacklisted, so i'm a bit helpless !