Everything working except custom dns for domain.com

Morning everyone,

Having a small issue which is causing lots of frustration. I have set everything up using box.domain.com and all seems to working great I can send and receive emails etc. I have setup the dns and nameservers etc too. THe issue I am having is that I have another webserver which will handle the domains sub domains and the main website being www.domain.com. The subdomains are working correctly and load the correct page on the other server but domain.com one still redirects box.domain.com for some reason. Does anyone know why?

Did you set a custom DNS A (and AAAA, if applicable) record for domain.com?