VIP ISSUES - Cant access with internal server via FQDN

Hello,

I am currently having and issue and was hoping someone will be of help. 

I did configured VIP and my internal server can be access externally with the FQDN. How ever, internal users 

cant access this server internal using the FQDN. It works with the servers internal IP adress but FQDN not.

Can someone give me a solution to this and if possible an explanation....

Thanks in adavance

Spike