MDM Lock

We have numerous devices that appear to be stuck at the Remote Management sign in screen after being reset.

These devices have been acquired through various company acquisitions and the company name (before redacted) is correct. However, nobody in our corporate IT know which MDM Server/policy is applying to them or are able to log in.

My question is how can we determine where/which MDM server is applying the policy? I’m not asking to bypass but we’re unable to find these devices in our infrastructure.

Many thanks