Plesk Webmail Mismatch Configuration Files
1) If there is a Plesk webmail mismatch or configuration issue, please check the two below files:
a) /etc/httpd/conf/plesk.conf.d/roundcube.conf (This can be replaced with the configuration file for the webmail being used) – Takes precedent and disregards the second file
b) /etc/httpd/conf/plesk.conf.d/webmails/roundcube(Can be replaced with the configuration file for the webmail being used)/domain_webmail.conf