Hi,
A 503 Service Unavailable error in OneDrive usually means the service is temporarily unable to process your request. In most cases, this points to a server-side issue on Microsoft’s end rather than a problem with your device, browser, or files.
You can first check the Microsoft Service Health Status page to see if there is any temporary outage affecting OneDrive in your region:
https://portal.microsoft.com/servicestatus
Meanwhile, please try the following steps to help isolate the issue:
• Test using different browsers such as Chrome, Firefox, or Edge to see if the same error appears.
• Open an InPrivate or Incognito window to rule out cache or extension-related issues:
https://support.microsoft.com/edge/browse-inprivate-in-microsoft-edge
• Try accessing OneDrive using a different network, such as a mobile hotspot. If it works on another connection, the issue may be related to your current network.
If the issue still persists after trying the steps above, I would recommend waiting 24 to 48 hours and trying again later, as these types of service interruptions are often temporary.
You are also not alone in experiencing this issue. Other users have recently reported similar OneDrive 503 errors here:
https://learn.microsoft.com/en-us/answers/questions/5885085/503-service-unavailable
https://learn.microsoft.com/en-my/answers/questions/5885372/503-service-unavailable-when-i-try-to-go-on-one-dr
https://learn.microsoft.com/en-us/answers/questions/5888481/onedrive-login-error-503-service-unavailable