I have been trying to set up the 3cx PBX with a Samsung Officeserv SOHO telephone system. The 3cx software appears to be set up correctly, and is working and registering with an Android handset. However, when I try and register the Samsung phone, it comes up with the following error: 18:11:06.028 [CM102001]: Authentication failed for SipReq: REGISTER 192.168.1.9:5060 tid=-449949dd-f6c889ab-fd54834 cseq=REGISTER firstname.lastname@example.org:5060 / 22 from(wire); Reason: Credentials don't match, check that authorization-ID and password match the ones in extension settings The Samsung SOHO is set up as follows: Proxy Server: 192.168.1.9 Domain/Realm: 192.168.1.9 SIP Port (cannot change): 5060 The phone number / contact, user and password fields are the same as on the server. I have checked and double-checked, and the password / username are the same on both the device and the server. Is there anyone who has successfully configured this phone, or can spot where I might be going wrong - i.e. does the URI cause problems. I have noticed that the Samsung adds :5060 automatically at the end, and this cannot be changed. Many thanks in advance.