Domain Mapping Issue with parked domains

This is an issue of domain mapping. One domain is parked at the hosting of wordpress multi-site installation ( which add sub-sites as subdomains to Now we are facing problem while mapping to

The problem is that while adding the parked domain on the domain mapping settings page, health status is invalid and is not added.

It is also confirmed that the parked domain ping to same i.p. as that of main wpmu installation domain.

We are trying every documentation but the problem persists.

Any early guidance will be highly appreciated.