Hello, I have the same problem.
Ever since I connected to jagex account and accidentally logged out of mobile client, I can not log back in. I don't know if this is the cause or not.
I have tried reinstalling. Uninstalling after clearing cache and data, restarting phone and reinstalling didn't work either. I've also tried 5 different kinds of browsers to be default and different WiFi and my mobile data. None of these have worked.
The phone I am using (oppo reno 8) had no issues before the accidental logout.
22-Jun-2023 11:49:33