I am experiencing a problem with the NDR SH app that never appears to load properly with content. The NDR Kultur app on the other hand works fine. Not sure what is going on. I am using the latest version of Murena OS. I just flashed itto my Fairphone 4 today, and all of the other third party apps work fine so far.
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This could be a similar to Apps not working after updating FP4 to /e/OS 2.6.3, but we can only guess which of the Different Build Types and Android version. This can be remedied by
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Android version 14
2.6.3-u-20241217455359-official-FP4
I have tried uninstalling and reinstalling the app.
Hmm, how does this problem manifest?
I have FP4 with same version e-os, installed NDR SH for the first time ever 
Just watched a dolphin jumping aroind in Kiel canal apparently Is there something else that should be loading but isn’t?
There are four functions at bottom of app to select. The first works today. The second partially works today (streaming radio is accessible), but nothing in the upper or lower panes is loading. The last two functionalities keep loading, but nothing appears.
I don’t know if it makes a difference, but I am at this time testing Murena OS without a sim card. I am only connected by wifi.
Ok, now nothing is loading for me - just the gradient going left to right everywhere. After restart top of the pane Nachrichten worked so I could see the dolphin video again and some others but nothing it the lower parts of the page. Unlike on my first run when I could see all (?) videos thumbnails on that page.
And now nothing on any other pane / function. So it actually worse for me now than it is for you 
VPN on or off doesn’t have any effect
There isn’t anything working for me anymore either. Not even radio streaming. I can’t find a pattern in this problem.
I wondered if this was limited to Fairphone / FP4 ? I have a testing build so am prevented from test + comment. Also I barely understand German.
However the app installs, and plays free content fine, and seems to allow registration, although I haven’t actually followed through, on my Moto G(7)Power ocean with
2.6±u-2024xxxxxxxx-community-ocean
It would be strange + interesting if the poor behaviour was one device and build only.
It would seem to merit Report an issue especially if a logcat could be obtained.
FWIW, I have also installed the NDR SH app, and it seems to work fine on my OnePlus 6 with /e/OS 2.6.3 U, community edition. So it may indeed be related to the device? (correction, see comment below)
(Apart from that, the app was a nice reminder of my PhD time at Kiel University 
)
I have to correct myself: I did not take into account that I have installed another webview (I used the Magsik module OpenWebView, with the Mulch Webview v131). If I revert to the original webview of /e/OS (v130), I also get several problems with the NDR SH app.
So it seems indeed to be a webview problem (either upstream with v130, or with some modifications done by Cromite, on which the /e/OS webview is based).
There is a bug report on the /e/OS GitLab regarding WebView problems (although on a Galaxy S7 with /e/OS S 2.6.3): No browser, and all webview-related apps crash on 2.6.3-s on Samsung Galaxy S7 (#8457) · Issues · e / Backlog · GitLab
Maybe the problem is related to this one?
EDIT: Is the problem still present in /e/OS 2.7? The webview should have been updated (I cannot check myself because I have not installed /e/OS 2.7 yet).
Just tested on my FP4 running 2.7-u-20250109460370-official-FP4 and it seemed to work fine:
Cheers!