Hi @Elli Goss ,
This is a server-side issue (500 error on StartupData load), not something wrong with your device. A few things to try:
- Hard refresh the page (Ctrl+Shift+R) or clear browser cache/cookies for outlook.office.com.
- Try a private/InPrivate window to rule out extensions or cached data.
- Try a different browser, or the desktop/mobile Outlook app, to see if the issue is limited to OWA.
- Check Service Health in the Microsoft 365 admin center (Health > Service health) for any ongoing Exchange Online incidents.
If none of that works, this needs to go to your tenant admin or Microsoft support with the error details, since it's a 500 from their backend (efe: LO4P302CA0025). The reqid and cv values in your error are what support will need to trace it on their end.