Literally the exact same problem this person had and got solved: https://help.forumotion.com/t136018-personalized-domain-name-keeping-getting-deleted

I have my own domain name, I set up the CNAME and verify it on the ACP.  Everything works fine but after a few hours, my forum auto deletes the personalized domain.  I have purchased two domain names through you before so I think the forum still thinks one of those old domains is still active so it deletes my personalized domain name.

Please help me, thanks.

Hello

Without the following information, we cannot here you:
- Url of your forum
- Cname
- Description of the problem
- Screenshot

Regards 

My forum url is 
My CNAME is 
My problem is my forum auto deletes my personalized domain name after a few hours for no reason at all.  Why does it keep deleting for no reason at all?  Is it because I owned two prior domains through forumotion and it thinks the old domains are still active?

Are you pressing the save button after entering the domain name?

Hello

Indeed, there was a little problem with our database. You bought a domain name with Forumotion in 2013. Sometimes, the domain name is not well deleted. By consequences, there is a conflict between the FM domain name and the CNAME.
Now, we fixed the problem. Please check tomorrow and let us know if the Cname is properly sets up on your forum.

Sorry for the trouble.

Best Regards

Buttercup 

Hello

Indeed, there was a little problem with our database. You bought a domain name with Forumotion in 2013. Sometimes, the domain name is not well deleted. By consequences, there is a conflict between the FM domain name and the CNAME.
Now, we fixed the problem. Please check tomorrow and let us know if the Cname is properly sets up on your forum.

Sorry for the trouble.

Best Regards

Buttercup 

Solved, thanks