I have tried installing CP on different VPS’s with Centos8 but each time when I create an email address then go to ‘access webmail’, I get authentication error (as if the password is wrong). It works fine on Cento7 but I would rather use 8 but need to create email addresses?
I have the same problem, I made an e-mail inbox but I can’t log in to it.
Let’s say your domain is example.com
You could try to restart postfix : sudo service postfix restart.
If you can go to rainloop admin: Make sure in security → SSL is uncheck for require verification of SSL certificate.
I have the same problem before but that above solved my problem to login.
Ok this resolve problem 2 - SSL For PostFix/Dovecot - CyberPanel