RDP to Azure VMs suddenly stopped working with certificate error

Question

I've had two Azure VMs working perfectly fine for over a year with RDP. They're domain joined and used Windows Hello to log in. As of 4/20/25 they've stopped allowing access and are throwing the following error upon RDP attempts to connect:

A certification authority could not be contacted for the authentication. If you are using a Remote Desktop Gateway with a smart card, try connecting to the remote computer using a password. For assistance, contact your system administrator or technical support.

Error code is the generic 0x0.

I've made no changes to the environment whatsoever and they were all working as of last week with no issues. I suspect a certificate expired somewhere, but for the life of me I'm not sure where/how.

Answer 1

So I went through most of that and none of it worked. However, it suddenly started working again on its own. So we're obviously looking at an issue on Microsoft's end. Therefore, no solution except wait for Microsoft to fix their server(s)) on this one, I guess. But thank you for your input!

Answer 2

Follow https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/troubleshoot-rdp-connection

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hth

Marcin