Domain mapping – health status invalid

I understand it can take some time for domain mapping to take effect. If it has been done successfully, would it be normal to see a message of “Health status: Invalid” until the propagation has taken place? Or does this indicate another problem?

I am attempting to map example.com to sub.domain.com, but I am getting a health status of “Invalid”. Example.com is up and running at this moment.

At my registrar, I have amended the A record of example.com to point at my server IP (I maintain my own WHM server with cPanel). Actually I had two A records at the registrar that looked like they should be changed. These were the STAR host and the host labeled “example.com”. I changed both of these to point at my server IP.

The nameservers are not set to the default registrar setting. They are pointing at my own DNS server, which is in turn directing to the IP of the server that example.com is hosted on. This is the same server that my multisite is hosted on.

Do I just need to wait, or is there something else wrong somewhere?

Thanks!