Waipu PVR or Video Addon, Live TV working Recordings not working, only on CoreElec

I’m using CoreElec 21 on an S905x4 Box. Everything is working fine excerpt for cloud- recordings in Waipu (German IPTV and VOD service). There are two Kodi addons for Waipu. the “official” PVR addon and an older but still working video addon. Both are showing the same behaviour. Live TV is working, recordings are not working.

2024-04-12 17:49:44.521 T:1278    error <general>: AddOnLog: pvr.waipu: [Http-GET-Request] error. status: 401, body: <html>
                                                  <head><title>401 Authorization Required</title></head>
                                                  <center><h1>401 Authorization Required</h1></center>

Here ist the relevant part from a debug log… It looks as if the credentials are not valid but if they aren’t Live TV also would not work. This was working with CoreElec 20 but since 21 it didn’t work any longer. On other OS (Android, Windows) the plugins are working, so it seems to be a CoreElec issue…
Thanks for having a look at this.