Rainloop - Authentification failed

I do not understand why I keep having this error in Rainloop:

Authentification failed.

There was no error during installation, if anybody can guide me, I will be grateful.

I probably installed cyberpanel 10 times but to no avail.
Thank you

This is the error
dovecot: auth-worker(1642): Error: sql(hello@DOMAIN.xyz,127.0.0.1,<MdVB9s3EFqJ/AAAB>): Invalid password in passdb: crypt() failed: Invalid argument

This is the error
dovecot: auth-worker(1642): Error: sql(hello@DOMAIN.xyz,127.0.0.1,<MdVB9s3EFqJ/AAAB>): Invalid password in passdb: crypt() failed: Invalid argument

Finally found the issue, I installed on Ubuntu 18, I changed to Ubuntu 20 and now no problem. Thank you all