Alberto, go into your Quintum and type “gk ep” from your CLI prompt. That will tell you if the ATA 186 ever registered with the Quintum.
The phone number format should be the same, meaning country code first,area code and number.
Also you could try to type ev from the cli.
it go into debugging mode and let you see the messages betwen your ATA and Quintum Hard to descipher,but worth a try.
Look for I.P. addresses on the registration process.
be sure that you are not behind a nat on the ATA.
Look for confirmation or reject from the gatekeeper of the Quintum.