Hello!
I have fixed the issue by removing the roundcube and do the following tasks:
1. Remove roundcube directory -
/var/lib/roundcube2. Download the
roundcubemail-1.5.3-complete.tar.gz from
https://github.com/roundcube/roundcubemail/releases/tag/1.5.33. Copy to
/var/lib/roundcube4. Extract it using this command:
tar -xf roundcubemail-1.5.3-complete.tar.gz5. Run mail.domain.tst/installer to configure it
6. When you get temp/: NOT OK (not writeable for the webserver), feel free to run:
chown -R www-data:www-data /var/lib/roundcube/temp/7. Remove the installer directory to protect it from unauthorized access and open: mail.domain.tst.
Now, it should work well and without any issue.
The issue is resolved. Thank you.