One reason that might happen … do you have a clear wifi connection while you try to save the APN. I believe the device will try to confirm with a database that your new setting is on the database before allowing the “save”.
Ofc, as this is a roaming problem, the issue could be quite different!
Thank you for the suggestion! I have tried again (reset the APNs and insert again EDIT: while on good wifi), but no luck - the new APN simply disappears. What is interesting is that it disappears only when I set non-default MCC and MNC numbers… Weird.
I did also notice that I can’t manually select the mobile network because the list is always empty… Automatic selection however works and the signal strength is great. (EDIT: solved this part by selecting a different Preferred Network Type, it now shows the providers)
I’m on latest version (1.1) if it matters… I’m guessing I have disabled something I shouldn’t have?
Thank you both for your help! It turns out that my provider sends APN settings through some notifications which (I think) use Google cloud. No G - no settings… They have now sent me an SMS with the correct APN and it works.
The reason I could not enter APNs is that android “helpfully” hides all non-applicable entries. The MCC/MNC must actually match my provider, not the foreign one… So one can only get the APN data fron their provider.
Anyway, all works now, and I have learned a ton. Thank you!