What phone number checks happen with Identity Verification?

My MAICPP enrollment was rejected at the identity verification step with "primary contact details did not match" and no further detail.

I'm trying to understand whether the primary contact phone number plays any role in this check before I reapply.

Specifically: Is the number checked for line type (mobile vs virtual), or is it just stored as contact info with no verification role?

Support tickets keep getting closed with links to articles that don't cover this. Any insight appreciated.