Remote sip phone can't register

Hi, all

I have a danymic sip phone in * and they work fine in local network, * and sip phone are in same LAN. My * has a public IP address behind a NAT, NAT/FW opens all port for this host IP. I take this sip phone to remote, it can’t register to * . (I use public IP at there) . In sip.conf, I set : (my public ip)
localnet= --> this my local ip

SIP phone register to * , * display 403 error.

I use same extension config & same device , only * server IP is different.

Why can i get diffrent result ??

Pls help , thks

Remote better use IAX extension.But you are remotely using the client system and Asterisk server in same network then SIP will work No probs.