Hi Patrick, I dont know the answer to your problem, but just to claify, the password is never stored in the app. When you enter your username and password in the app, it is sent to the Moodle server, which generates a Web Service Token and sends that back to the app. The app stores this token and sends it to Moodle with every request to tell it which user you are.
It's possible that this token is being deleted or expired at the server end, so when the app sends the token it asks you to log in again. You could take a look at /admin/settings.php?section=webservicetokens to see if it has an entry for your user.
I don't believe $CFG->disablelogintoken is related to web service tokens, its used for CSRF protection on the login form. If you're using a custom login form, you might have had to disable this for it to work.
[Tue Aug 20 06:28:40 2019] [-:error] [client XXXXXXXXXXXXXXXX:47421] Debugging: Did you remember to make the first column something unique in your call to get_records? Duplicate
value '2' found in column 'category'. in \n* line 1254 of /lib/dml/mysqli_native_moodle_database.php:
call to debugging()\n* line 1400 of /lib/dml/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()\n* line 218 of /calendar/externallib.php: call to moodle_database->get_records_select()\n* line 1444 of /webservice/lib.php:
call to core_calendar_external::get_calendar_events()\n* line 1290 of /webservice/lib.php: call to webservice_base_server->execute()\n* line 44 of /webservice/rest/server.php: call to webservice_base_server->run()\n
[Tue Aug 20 06:28:42 2019] [-:error] [client XXXXXXXXXXXXXXXXX:47421] Default exception handler: Notwendiger
Parameter "username" fehlt Debug: \nError code: missingparam\n* line 494 of /lib/setuplib.php: moodle_exception thrown\n* line 566 of /lib/moodlelib.php: call to print_error()\n* line 34 of /login/token.php: call to required_param()\n