Troubleshoot service issues
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This section addresses issues that might arise as you use the Microsoft Defender for Endpoint service.
Server error - Access is denied due to invalid credentials
If you encounter a server error when trying to access the service, you'll need to change your browser cookie settings. Configure your browser to allow cookies.
Elements or data missing on the portal
If some elements or data is missing on Microsoft 365 Defender it’s possible that proxy settings are blocking it.
Make sure that
*.security.microsoft.com is included the proxy allowlist.
You must use the HTTPS protocol when adding the following endpoints.
Microsoft Defender for Endpoint service shows event or error logs in the Event Viewer
See Review events and errors using Event Viewer for a list of event IDs that are reported by the Microsoft Defender for Endpoint service. The article also contains troubleshooting steps for event errors.
Microsoft Defender for Endpoint service fails to start after a reboot and shows error 577
If onboarding devices successfully completes but Microsoft Defender for Endpoint does not start after a reboot and shows error 577, check that Windows Defender is not disabled by a policy.
For more information, see Ensure that Microsoft Defender Antivirus is not disabled by policy.
Known issues with regional formats
Date and time formats
There are some known issues with the time and date formats.
The following date formats are supported:
The following date and time formats are currently not supported:
- Date format yyyy/MM/dd
- Date format dd/MM/yy
- Date format with yy. Will only show yyyy.
- Time format HH:mm:ss is not supported (the 12 hour AM/PM format is not supported). Only the 24-hour format is supported.
Use of comma to indicate thousand
Support of use of comma as a separator in numbers are not supported. Regions where a number is separated with a comma to indicate a thousand, will only see the use of a dot as a separator. For example, 15,5K is displayed as 15.5K.
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Microsoft Defender for Endpoint tenant was automatically created in Europe
When you use Azure Defender to monitor servers, a Microsoft Defender for Endpoint tenant is automatically created. The Microsoft Defender for Endpoint data is stored in Europe by default.