Outlook Mobile is not getting any refresh tokens

We’ve recently encountered an issue with the Outlook Mobile app on Android devices (Motorola) within our organization. After several days of research and troubleshooting, we managed to test a few things and came to some observations:

We disabled battery optimization and data saver for all Microsoft apps on the affected phones.

Each user is receiving a “failed non-interactive sign-in” with different error codes, but they all seem to be related to refresh tokens. We suspect the apps may be having trouble fetching new tokens, or the device is killing processes in the background.

Interestingly, the devices are performing regular check-ins in Intune without any issues.

The main problem users are experiencing is that Outlook Mobile periodically stops receiving emails for a period of time — sometimes for an hour, sometimes longer. Refreshing or forcing synchronization does not resolve the issue.

Has anyone else run into this problem? Is there a known solution or workaround?