No Alex, by manually browsing the list I was finally able to locate the account that is causing a problem.
As you can see, he does not have a profile.
Problem, if I try to delete it, the wheel turns indefinitely.

Also, I try to reset the password of the account, then tried to connect to it, this produces a 500 error. It looks like a corrupt account somewhere ...

I can see this account in the sys_account table ...