[SOLVED] 504 bad gateway connecting to roundcube. /admin accessible fine

[ilyadr]

Using for a year MIAB starting with version 0.21 (I think). After upgrading to version 0.26 I have a problem when I can access /admin, but from time to time when I go to /mail I get the login screen, but submitting the form results in a “504 Gateway Time-Out” error.
The problems exist up to an hour then Roundcube is accessible again for some time.
Feels like Roundcube goes to some kind stndby mode. And you need to pull it several time for it to awaken.
The MIAB was installed on DigitalOcean droplet, then migrated to Linode with no success.
Version upgrade also doesn’t help. No MIAB is 0.30 version.
System monitoring doesn’t show any 100% resource consumption. Memory is 60% free (out of 4Gb). Disk space more than 60Gb available.

@murgero, help please

Fixed setting parameter pm.max_children=50 in www.conf

[alento]

Hi ilyadr

Undoubtedly @murgero will ask to see logs from when this happens. Can you post them?

[murgero]

@alento is right, Please PM logs as they can hold sensitive information.