Is it possible to restrict users from using email outside of webmail? I just want to allow only webmail access for certain domains and not any other email clients.
No currently not…
You could Block External Access to Ports 465 587 143 993 using the Hestia Builtin Firewall Configuration
Yeah thought of that but it would also affect the domains that aren’t restricted too.
Roundcube uses the same protocol as IMAP it not possible.