I have 3 pstn lines connected to a Grandstream 4104. I am unable to receive incoming calls on line 3 of the Grandstream. Lines 1 and 2 are working perfectly. Lines 1,2 and 3 set up as 10000, 10001 and 10002 so trying to dial in on 10002. Grandstream status page showing phone number 1,2 and 3 as registered and pstn lines 1,2 and 3 as connected and idle. 3CX ver 10 Ports/Trunks Status showing all 3 lines as green registered and idle. I get this error in the Server Activity Log when calling: 16:19:37.195 [CM102001]: Authentication failed for SipReq: INVITE firstname.lastname@example.org tid=b7927ee18fb29da5 cseq=INVITE email@example.com:5064 / 24729 from(wire); Reason: Credentials don't match, check that authorization-ID and password match the ones in extension settings I have a single inbound rule for each line redirecting to the same extension. Can anyone offer any insight into this?? Thank you in advance.