Fix an issue with Dovecot Crypt Plugin passwords (mail client can't decrypt/show emails)

We are setting up a Dovecot mailserver with Mail Crypt plugin for email encryption. We have set up per-user encryption, emails are getting encrypted, can be sent and received. However, webmail (we use SOGO) is unable to decrypt emails. We suspect that there is an issue with the passwords, respectively they are not being passed to webmail or this is being done incorrectly. Passwords are being stored in a mysql database. We need to fix this issue and make webmail read/show encrypted emails.