[SOLVED] Contact IP and External IP not matching?

The contact IP is set to my freePBX server’s LAN IP and the external is literally set to the external IP freePBX detects.

What is the contact IP purpose? Could you give me insight on its functionality?

I think I am suppose to set it to my external however I very cautious changing any settings without understanding why.

Thank you

Go to Asterisk SIP settings then click detect external IP.
Set up local networks with gateway and subnet mask.

Click Chan SIP over on the right.

Override external IP>> make sure this has no values inside. * external IP should be faded.

For some reason having a value in the Override external IP upset my system. I am curious as to why but I have yet to find an answer.