PSTN Callers not Hearing any Ring Back When they Call DID flynumber

I forwarded my flynumber to my freevoipdeal account.
Problem:
Callers are not hearing any ringback, while the phone on the SIP device is ringing.
I tried on SPA112 device and a Zyxel voip device. Both devices show the same issue.
Hope you could help me out. I spent too much time testing and figuring out what the issue could be.

I just purchased a number at Callcentric and configured it exactly the same.
There it works. Any tips on getting my flynumber a ringback?

This could be due to a number of factors but its usually fixed when forwarding with our PBX / Virtual Phone System.

You can set the same forwarding with the PBX ( No extra costs either)

Its newer technology and can help…

We can also set this for you, please open a ticket and it will be handled ASAP