asterisk users - May 2020 - SIP/2.0 401 Unauthorized

Hello I use Asterisk 13 with FreePBX.
When I try to connect my Softphone via VPN to Asterisk I'm registered
and It's show via "pjsip list contacts"

Then I try to call an internal number / other extension I get the
following: "SIP/2.0 401 Unauthorized".

The VPN net is list in
pjsip.transports.conf:local_net=10.8.0.0/24 and
sip_general_additional.conf:localnet=10.8.0.0/24

I'm not sure whats wrong here.
Best Regards