Prerequisites

• I have searched for duplicate or closed issues
• I can recreate the issue with all plugins disabled

Describe the issue

I am testing the new RCM version 1.7 RC4 and configure SQL using an IPv6 address like [fd00:3::10], but RCM can't parse those and fails with the Oops screen.

This is configured in config.inc.php for SQL:

$config['db_dsnw'] = 'pgsql://user:password@[fd00:3::11]/roundcubemail';
$config['db_dsnw'] = 'pgsql://user:password@10.10.3.11/roundcubemail';

The first connection string don't work, the second connection string does work (used one at a time).

This was originally fixed for MariaDB in bug report #9937.
In this bug report, I am using PostgreSQL.

What browser(s) are you seeing the problem on?

Firefox

What version of PHP are you using?

8.4.16

What version of Roundcube are you using?

1.7 RC4

JavaScript errors

None.

PHP errors

[03-Mar-2026 15:44:48 +0000]: <3a755022> DB Error: SQLSTATE[08006] [7] connection to server at "[fd00:3::11]", port 5432 failed: timeout expired in /opt/roundcubemail/1.7-rc4/program/lib/Roundcube/rcube_db.php on line 186 (GET /)