I cannot add new email accounts

When i try to create a new account i get the error "Failed. test@test.com cannot be created"
I tried from different user account but nothing. I also check the packages limits, postfix passwd and nothing.
And of course i rebuild the mailserver and reboot with no success. I do have old email account and so i dont know in which point it stopped to be able to create new accounts.

contact support for the checks, and mention this topic link there.

I've just done a quick test of creating a new email on  CWPpro version: 0.9.8.1020
There were no issues apart from emails bouncing, due to no email validations - which didn't surprise me as the email account had just been created.

[Edit]
On a different server I see the messages undelivered and..

(temporary failure. Command output: Can't open log file /var/log/dovecot.log: Permission denied)
                                         tester@xxcloud.xxxxxservers.com

I suspect there's a different problem with this though. Same CWPpro version but this one has all the clamd/amavis/spamassassin stuff enabled.

I do have email accounts that working fine, but created a long time ago. Now i just cannot create new one. At any user/domain.