Error code 0x2407 when trying to connect my MacBook Air to a Windows PC using Microsoft Remote Desktop

Hey Guys, would really appreciate any suggestions for my issue.

I have a MacBook Air, running on Big Sur. I'm trying to connect to a PC in my school via the Microsoft remote desktop app. I select add PC, put in the details I was provided from my college (host name + my personal login details). It tells me the certificate couldn't be verified back to the root certificate. Your connection may not be secure. I click continue. Then every time I get error code 0x2407 and I can't connect it.

I've read a few posts on the topic and tried removing some of the preferences in the Microsoft Remote Desktop app and using the Beta version of the app.

My college IT support has been no help and just tell me to check my Mac settings, but I'm not sure exactly what needs changing.

The error message reads: " we couldn't connect to the remote PC. You might not have permission to sign in remotely. Contact your network administrator for assistance".