Oh, sorry for that I am running the free version indeed.
I have replaced the 2 user.py files and restarted but it seems the problem is still there, furthermore I can't seem to be able to add new users form the iRedmail admin panel, I am getting: internal server error, which didn't happen before.
How can I update or change the password for this postmaster user? I don't see it in vmail - admins table, maybe I deleted it by mistake.
Thanks for you help