Phones suddenly stopped working - Loops in Register, 407 Proxy Authentication Required

[angeraer]

I have some legacy Grandstream phones that I'm using in a POC setup to validate the 3CX solution.
It was running, but suddenly it stopt working. A packet capture on the phone shows that the phone is sending the REGISTER towards the PABX (in the cloud). The PABX sends a 407 Proxy Authentication Required to inform the phone to authenticate and there it seems to stop and loop indefinitely.
I know the phones aren't supported, but they worked for some weeks. I'm not aware of any changes that could have an impact on this and don't understand why the phone isn't passing the correct information.

This is the capture information taken on the phone. The same behavior is seen on the PABX. I don't see any other logs that indicate where to look?

REGISTER sip:safevoip-demo.3cx.be SIP/2.0

Via: SIP/2.0/UDP 84.193.162.64:5060;branch=z9hG4bK1607428337;rport
From: <sip:[email protected]>;tag=952255108
To: <sip:[email protected]>
Call-ID: [email protected]
CSeq: 2034 REGISTER
Contact: <sip:[email protected]:5060>;reg-id=1;+sip.instance="<urn:uuid:00000000-0000-1000-8000-000B82953DB2>"
Proxy-Authorization: Digest username="o35dcho", realm="3CXPhoneSystem", nonce="414d53595a2f61e214:da510c9361a7deb240a60660249101c4", uri="sip:safevoip-demo.3cx.be", response="8d49c5190c9e12c969b50abec32c5d60", algorithm=MD5
X-Grandstream-PBX: true
Max-Forwards: 70
User-Agent: Grandstream GXP2140 1.0.9.26
Supported: path
Expires: 3600
Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE
Content-Length: 0

SIP/2.0 407 Proxy Authentication Required
Via: SIP/2.0/UDP 84.193.162.64:5060;branch=z9hG4bK1020916491;rport=5060
Proxy-Authenticate: Digest nonce="414d53595a2f61e214:da510c9361a7deb240a60660249101c4",algorithm=MD5,realm="3CXPhoneSystem"
To: <sip:[email protected]>;tag=dc5bcb01
From: <sip:[email protected]>;tag=1310528689
Call-ID: [email protected]
CSeq: 2032 REGISTER
User-Agent: 3CXPhoneSystem 15.5.6354.2 (6354)
Content-Length: 0

REGISTER sip:safevoip-demo.3cx.be SIP/2.0
Via: SIP/2.0/UDP 84.193.162.64:5060;branch=z9hG4bK1607428337;rport
From: <sip:[email protected]>;tag=952255108
To: <sip:[email protected]>
Call-ID: [email protected]
CSeq: 2034 REGISTER
Contact: <sip:[email protected]:5060>;reg-id=1;+sip.instance="<urn:uuid:00000000-0000-1000-8000-000B82953DB2>"
Proxy-Authorization: Digest username="o35dcho", realm="3CXPhoneSystem", nonce="414d53595a2f61e214:da510c9361a7deb240a60660249101c4", uri="sip:safevoip-demo.3cx.be", response="8d49c5190c9e12c969b50abec32c5d60", algorithm=MD5
X-Grandstream-PBX: true
Max-Forwards: 70
User-Agent: Grandstream GXP2140 1.0.9.26
Supported: path
Expires: 3600
Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE
Content-Length: 0


SIP/2.0 407 Proxy Authentication Required
Via: SIP/2.0/UDP 84.193.162.64:5060;branch=z9hG4bK1020916491;rport=5060
Proxy-Authenticate: Digest nonce="414d53595a2f61e214:da510c9361a7deb240a60660249101c4",algorithm=MD5,realm="3CXPhoneSystem"
To: <sip:[email protected]>;tag=dc5bcb01
From: <sip:[email protected]>;tag=1310528689
Call-ID: [email protected]
CSeq: 2032 REGISTER
User-Agent: 3CXPhoneSystem 15.5.6354.2 (6354)
Content-Length: 0

Same view on the PABX:


Any idea where to look?

Andy.

 

[NickD_3CX]

Check the IP Blacklist in case the Public IP of the location where the phones are at is in there. Also check if the Auth ID and Passwords are still the same, maybe someone re-generated them?