Hi @Gebauer, Roman,
Welcome to the Microsoft Technical Support Forum.
Based on your description, the error you are experiencing usually indicates a problem in the HTTP request/response cycle and is usually related to configuration issues in IIS, authentication settings, or Exchange redirection settings.
I recommend that you follow some of the following troubleshooting steps:
1.Check Redirect Settings in IIS:
- Open IIS Manager.
- Navigate to the
Default Web Site
. - Select the HTTP Redirect feature.
- Ensure that redirection settings are configured correctly or disable them if they are not needed.
2.Sometimes, issues in the web.config
file can cause such errors. Look for any custom redirection rules or errors in the web.config
file for OWA and ECP.
The web.config
files are usually located in C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\owa
and C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\ecp
.
3.Re-check the authentication settings for the OWA and ECP directories in IIS:
- Open IIS Manager. - Navigate to the
Default Web Site
and select theowa
andecp
directories. - Under the Authentication feature, ensure that Basic Authentication and Windows Authentication are enabled, and Anonymous Authentication is disabled.
Please feel free to contact me if you have any queries.
Best,
Jake Zhang