Hello! I have some trouble to connect a Patton 4114 FXS to may 3CX. The Patton is properly provisioned but don’t show up in the 3CX “phones” section. After a while 3CX blocks the IP of the Patton for “too many failed authentications”. I captured the communication between the Patton and 3CX and what I can see is that the Patton performs “REQUEST: REGISTER SIP: 172.31.X.X:5060 SIP/2.0” and 3CX answered with a “STATUS: SIP/2.0 407 PROXY AUTHENTICATION REQUIRED” there are now other packets captured. Network layout: - Patton sits in 192.168.5.0/27 subnet - 3CX sits in a 172.31.16.0/20 subnet - Both subnets are connected together via VPN Does someone know how to solve this problem? If you need further information please let me know. Thank you!