Error 0x904 is purely a certificate trust mismatch . It is not a bug but a security feature preventing you from connecting to a server whose identity cannot be verified. The correct fix is to install a trusted certificate on the RDP server matching the connection hostname.
If you have local access to the server, open the Certificates Manager ( certlm.msc ), find the expired certificate under Remote Desktop > Certificates , and delete it. Afterward, restart the Remote Desktop Services in the Command Prompt as an administrator using restart-service termserv -force . Windows will then automatically generate a fresh certificate. i remote desktop connection error code 0x904 better
Log into the affected host locally or through an alternative remote tool. Error 0x904 is purely a certificate trust mismatch