Altigen IP710 phone compatibility issueswith freepbx?

here is my setup:

endian firewall with two sub nets dhcp) , dhcp)

freepbx installed on

setup trunk from successfully/ setup extension 1001 PW: 11111 . strong password turned off

on the altigen phone i put as server, turned off dhcp and gave it a static ip, gateway, subnet

when i register the extension it says sip reg failed

and with some tweaks of the settings on the phone like enabling & disabling nat/auto discovery i get stuck on “registering”

i just installed zoiper and i successfully registered ext [email protected] and it was able to call another desktop with ext [email protected]

so is this a compatibility issue?
does altigens firmware need an upgrade?
is there a codec it uses? i currently have the default codecs checked

thanks all