Domain Mapping to works but not if i put

I have recently came across this problem while mapping to a new domain for a client on my multi site

Problem : (see attached) As you can see I tried mapping my domain I went into the said domains DNS and changed the A record to my static ip address. I mapped it to and it worked pointing to the website that is on my multi site but than I tried to map it to and it shows the status as invalid and points to the old website. What did I do wrong?

Things to know:

1.) I have about 15 domains on my multisite that the domain mapping is working fine on

– Because of this I know my initial set up for domain mapping is not a problem.

2.) my static ip address is