Domain Status show Possible service issues with MX having Error but checked MX Record its the same

Hi, 

Just found out that Microsoft 365 Admin Centre > Domains show custom domain having Possible service issue status.

When clicked into it, it shows MX status having error.

Did a nslookup -type=MX "xxxx.com"

and did a comparison with DNS MX Record, It shows exactly the same value as Microsoft 365.

Not sure what is exactly the issue.

We did not make any amendment to any settings.