Successfull connection of GN Resound Hearing Aid to FP6?

Has anyone already succesfully connected a GN Hearing aid to their FP6 with Android?
We’ve tried multiple times without success, Bluetooth does recognize the hearing aid as we can see it paired in the settings. However the ReSound App calls for a restart of the hearing aids after this first pairing and this second one always fails with an error message. We have enabled the location and other asked for options within the phone.
Any tips are welcome as our mother really likes the GN Resound hearing aids after lenghty testing with her old phone (Xiaomi, which also isn’t listed as compatible with GN, but did work without bigger issues). However she really is in love with the FP6 which arrived just last week and now has the compatability issues.