S7 v1.0 mobile data not available for several apps and websites (APN-related?)

/e/ version: 1.0-20220526188859
Device model(s): Galaxy S7 (SM-G930F)
Device rooted: ? I bought the device in the /e/ shop in 2020
Mobile network provider: Congstar (Deutsche Telekom)

Summary

Several apps have no access to internet via mobile data (4G) anymore after OTA update/upgrade 0.19-20211023142428 -> 1.0-20220526188859

(Same apps and websites without any issues when wifi is ON)

Might or might not be related to issue #5628 (closed) (can´t reproduce the whole list of working /not working domains as described there)

Seems like the issue is related to APN settings (see below "possible fixes" and issue #5628 (closed))

There are more users experiencing the same (or pretty similar to the unarmed eye) issue:

edits: clarifications & additions

The problem

Steps to reproduce

All permissions for apps to use mobile data are granted, incl. background data
mobile data is ON,
wifi is OFF
advanced privacy is OFF
no VPN, no data saving mode, no battery saving mode

What is the current behavior?

DOES NOT work:

signal-app does not send nor receive messages - behaviour persists also after reinstall
browser (built-in default) does not connect to e.g. https://duckduckgo.com (" DNS_PROBE_FINISHED_NXDOMAIN")
app lounge tells me something about certain network errors and then crashes completely
nextcloud: does not sync, says "no server available"
wetter online-app has no internet - behaviour persists also after reinstall

DOES work:

wikipedia-app has internet access
FairEmail syncs with my posteo.de mail account
DAVx5 syncs with my posteo.de CalDAV calendar
browser (built-in default) does connect to e.g. https://blog.fefe.de OR https://uhr.ptb.de

What is the expected correct behavior?

everything that does not work as listed above is expexted to work instead :-)

Technical informations

Relevant logs (adb logcat)

Relevant screenshots

Solutions

Workaround

with wifi ON everything works OK so far

Possible fixes

--> doublechek/fix APN settings (no idea what happens to APN settings in the background during OS upgrade and why this works for some but not for others)

I got inspired by RD138´s approach. But other than in RD138´s solution/description there was no proxy defined in my APN-settings that I could delete… but I doublechecked the recommended APN-settings for S7 at my providers support-page (congstar.de). There is only recommendations for Android 6+7 available but in terms of APN-settings they are the same. So I tried and changed APN from “internet.telekom” to “internet.v6.telekom” as specified by congstar and left all other settings untouched.

et voilá: mobile data available again for e.g. signal-app… The other apps and websites seem to have access to internet via mobile data as well!

I want to point out that my previous APN-settings (= before the OS upgrade) were fully functional in terms of mobile network access.

Another user confirms this exact approach works in his case: https://community.e.foundation/t/mobile-data-issue-on-s7-after-upgrade-to-v1-0/41952/10?u=obacht

Other users found other specific APN settings to be altered in order to regain access to mobile network: https://community.e.foundation/t/no-mobile-data-connection-on-s7-edge/41678/8?u=obacht

but that "APN-settings approach" does not fully solve the issue for all cases as it seems - OR the issue might be somewhat different or other issues included: https://community.e.foundation/t/mobile-data-issue-on-s7-after-upgrade-to-v1-0/41952/8?u=obacht

[As of now and for my case I can say that only app-lounge still crashes very often (but after a few restarts at least has internet access via mobile data). There must be some other issue with that app that has little or nothing to do with mobile data...]

Checklist

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Documentation
Test plan

Edited Jun 26, 2022 by obacht8