Can anyone help me to find urgently solution (if exists)? I have migrated users from old imap server to ISPConfig/Dovecot Now users need to change configurations in all Mail clients to use 'username@domain' as loginname, instead of 'username' for old imap server. Since I have only one domain used for ISPConfig now. I wonder if I could find a way to configure Dovecot somehow to continue accept 'username' as loginname during 'imap-login', but to add my deafult '@domain' part for proper auth process to be done via ISPConfig. I understand that this is dovecot-config related, but would be very thankful if someone help me.