Issue problems occurred with the System Updates tool on your server

[ruiterples]

Hi,
I am getting this message on all Pleskservers (vserver and rserver) all run ubuntu 1604 or 18.04.

Some problems occurred with the System Updates tool on your server abc.abc.tld. Please resolve them manually.
Reason: 2022-03-26 06:25:14 INFO: pum is called with arguments: ['--list', '--repo-info', '--json']

At the end of the email is also
E:Failed to fetch http://autoinstall.plesk.com/pool/PSA_18.0.34_5691/dists/xenial/extras/binary-i386/Packages 404 Not Found [IP: 185.93.2.6 80], E:Some index files failed to download. They have been ignored, or old ones used instead.
2022-03-26 06:25:21 ERROR: Exited with returncode 1.

How do i solve that definitely or at least for a longer time?
I ran:
apt update
apt upgrade
several times but it keeps coming.

Regards,
Jan

 

[Maarten.]

Ubuntu 16.04 is no longer supported:

Feature Deprecation Plan

Learn about features that are going to be deprecated and/or removed from Plesk releases.

docs.plesk.com