T23G no audio outbound calls

Model: T23G
Firmware Version 44.80.0.95
Hardware Version 44.0.0.16.0.0.0
Server: Asterisk

We have to buy some new phones for our company so we have bought a Yealink T23G model to test this brand, unfortunatelly we immediately have an issue: inbound calls work fine but there is no audio on outbound calls to outside lines!

Any feedback would be greatly appreciated