Install Roundcube Webmail on Ubuntu 22.04/20.04 with Apache/Nginx
IMAP SSL Port 993 does not work get "Connection to storage server failed." error · Issue #5345 · roundcube/roundcubemail · GitHub
Roundcube connection to storage server failed [Fixed]
Install and secure a complete mail server (Mail, SMTP, Auth by SASL, IMAP, POP3, webmail, TLS and SSL) on Debian - Linux - Tutorials - InformatiWeb Pro