400 Bad Request Exchange Online Troubleshooting Guide
Introduction
Facing the “400 Bad Request” error in Exchange Online is a headache for many IT administrators and users. This error may occur when accessing web services such as Outlook Web App (OWA). In this article, we will explain in detail the cause and solution of this problem, and help your business run smoothly.
Cause of error
A “400 Bad Request” occurs when the server cannot process a request from a client because it is malformed or incomplete. Common causes for this error in Exchange Online are:
1. OWA Webmail App Disabled: This error may occur if OWA is disabled for a particular user.
2. Licensing issues: After converting a shared mailbox to a regular mailbox, you may encounter an error if the appropriate license is not assigned.
3. Malformed request structure: Occurs when a request is malformed or missing required information.
solution
Below are the solutions for the “400 Bad Request” error.
1. Check the OWA webmail app: In the Exchange Admin Center (EAC), check the email settings of the user in question and see if “Outlook on the web” is checked.
2. Verify license: Verify that the converted mailbox has the appropriate license and assign licenses if necessary.
3. Review detailed error messages: Review the detailed information displayed on the error page and follow the specific guidance to resolve the issue.
Additional information and advice
– Check your Active Directory settings: 400 Bad Request errors can occur related to your Active Directory settings. In particular, this error can occur if your account belongs to multiple Active Directory groups. Check appropriate group membership and adjust as necessary.
– Exchange server log analysis: Review server logs to determine the detailed cause of the error. Logs often contain detailed information about problematic requests and server responses, which can be useful for troubleshooting.
– Check your security settings: In rare cases, security settings or policies can block your request, resulting in a 400 Bad Request error. Review these settings, especially if the problem occurs after applying a new security policy.
Related Links
– [Spiceworks Community: O365 400 bad request]
– [Microsoft Support: Outlook Error 400 on web app]
– [Microsoft Docs: 400 Bad Request when you access the Options page]
We hope this article provides useful information to resolve the “400 Bad Request Exchange Online” issue and make your business run smoothly. If the error persists, please contact Microsoft or your IT professional for further assistance.
