22.04 – apt-get update outputs Error: Timeout was reached

Every attempt to run apt-get update ends in a timeout error:

sudo apt-get update
Hit:1 http://apt.pop-os.org/proprietary jammy InRelease
Hit:2 http://apt.pop-os.org/release jammy InRelease
Hit:3 http://apt.pop-os.org/ubuntu jammy InRelease
Hit:4 http://apt.pop-os.org/ubuntu jammy-security InRelease
Hit:5 http://apt.pop-os.org/ubuntu jammy-updates InRelease                            
Hit:6 http://apt.pop-os.org/ubuntu jammy-backports InRelease                          
Hit:7 https://ppa.launchpadcontent.net/diesch/stable/ubuntu jammy InRelease
Error: Timeout was reached
Reading package lists... Done

By what procedure can I determine the source of this error? Before that error appears the output does pause for about half a minute. It does appear to be waiting something that does not happen.

OS information:

lsb_release -a
No LSB modules are available.
Distributor ID: Pop
Description:    Pop!_OS 22.04 LTS
Release:    22.04
Codename:   jammy

This Pop!_OS version is based on Ubuntu 22.04