Sending, receiving, and organizing email in Outlook.com
Hi! Sorry to hear that you are having trouble with this. This thread is tagged as Outlook on the web, but from your description it seems the issue may be related to a mobile device. If that is the case and you are using iOS/iPadOS, Microsoft is currently investigating some service-side issues affecting access to Outlook and Hotmail accounts through the default iOS/iPadOS Mail app.
You can try the troubleshooting steps available in this Microsoft article:
You can also check the current Microsoft service status here:
https://status.cloud.microsoft/
Please review the troubleshooting options listed there and let me know if the issue continues after trying them.