Issue Roundcube sometimes shows "ALMALINUX" page

[tkalfaoglu]

Server operating system version

Alma Linux

Plesk version and microupdate number

Obsidian

Hi - a customer complained -- (and sent a video) that about 50% of the time when he deletes a mail in webmail, he gets the default web page, "alma linux apache bla bla" instead of the next message in the preview window. He says that this happens only when he is deleting mails in rapid succession..

In fact, sometimes he gets the "alma linux" default page covering the entire screen - no webmail visible anymore!
For privacy, I'm not enclosing the video, but if you are interested, let me know and I'll send it individually.

I'm enclosing our roundcube setup. Has anyone encountered anything like this?
Thanks! -t

PS: nothing unusual in /var/log/plesk-roundcube/errors

Roundcube Webmail 1.6.0​

Installed plugins​

Plugin	Version	License	Source
filesystem_attachments	1.0	GPL-3.0+
jqueryui	1.13.1	GPL-3.0+
managesieve	9.4	GPL-3.0+
markasjunk	2.0	GPL-3.0+
password	5.3	GPL-3.0+
twofactor_gauthenticator	dev-master	MIT	Download
zipdownload	3.4	GPL-3.0+

 

[tkalfaoglu]

PS: I checked the DNS entries -- both DNSs for their domain show the same and correct IP for webmail.domain.name

 

[tkalfaoglu]

I also thought about mod_evasive and modsec -- I think mod_evasive shows FORBIDDEN instead, and modsec would have logged something in its audit file.. they don't seem to exist.

 

[tkalfaoglu]

PPS: I was unable to duplicate the problem.. It always worked for my firefox linux..