Microsoft RDS with Azure Application proxy error- Gateway timeout - Connector did not response within timeout window

Question

Configured Microsoft RDS ( RDWEB+RD Gateway) with Azure Application proxy. when try to open the external URL, It prompt for username - password - MFA and after that give the Gateway timeout error.

Internal URL is working and able to access the application with internal URL

Remote address is not the address of my private connector

Answer 1

Hi @Sunil Saini

I understand that you've configured Microsoft RDS (RD Web + RD Gateway) with Azure Application Proxy. When attempting to access the external URL, you're prompted for a username, password, and MFA, but then encounter a Gateway Timeout error.

A Gateway Timeout error typically occurs when the service is unable to reach the connector within the designated timeout window. This often happens if the application is assigned to a connector group without any active/working connectors or the necessary network ports are not open.

To help resolve this issue, please review the following suggestions:

1. Verify the Internal URL is accessible by opening the application via Enterprise Applications > Application Proxy in the Azure portal.
2. Check Connector Group Assignment that the application is assigned to a connector group that contains at least one active and healthy connector. Refer to: Tutorial: Add an on-premises application for remote access through Application Proxy
3. Make sure all necessary ports are open for outbound traffic from the connector. For your reference: Add an on-premises application for remote access through application proxy in Microsoft Entra ID

As you mentioned, you've already verified the internal URL and observed through a network trace that traffic is not routing through your private connector. Please ensure that the application is correctly assigned to a working connector group to resolve this.