Solved Anonymous Callers Being Diverted Straight to Voicemail

[sac9829]

Having a strange issue with any number that is appearing as an anonymous number from our SIP trunk it is going straight to the voicemail box of the extensions the call should go to.

Tried setting up an Inbound caller ID rule to go to the correct extension but still goes straight to the voicemail box without ever ringing the extension.

Looking at the logs just shows that the extension is busy and diverts to voicemail but looks like the system is doing this automatically.

Where is the setting to control this so unknown or anonymous callers ring the extension just like a normal caller.

Edit: Have also checked the phones (Yealink T58) local settings and local anonymous reject is disabled on the phone so shouldn't be an issue.
3CX version is 15.5.15502.6

 

[eddv123]

Pretty sure this would be a 3CX problem.

I would use the binary log viewer event and activity logs to see why the call is being diverted, see below for this:

https://www.3cx.com/docs/3cx-log-viewer/
https://www.3cx.com/docs/collecting-logs-for-3cx-support/

 

[YiannisH_3CX]

Hello @sac9829

When an anonymous call arrives does it have a correct To: number? Unless you have an exception that diverts the call to voicemail the caller ID should not matter to the phone system. Are you using a supported provider?

 

[sac9829]

We are using a Generic SIP Trunk but everything else with this trunk is working without issues.

Checking with the trunk provider when we capture the call and look at the call headers we see it is arriving as an anonymous call.

If the caller doesn't have a blocked or unknown number then everything working without issues so is working 99% of the time without any issues but is just the 1% of callers which have a blocked number.

Can reproduce the error by changing a mobile to a blocked number instead of showing its caller ID and then the issue occurs.

Checking the call logs all the calls appear in the correct format as the inbound parameters seem correct. They are sent the same as a approved SIP trunk provider.

 

[cobaltit]

Being sent the same doesn't mean anything. There are many differences in how all of the current approved/supported providers send things down to 3CX. The difference is that the templates are already configured to produce the desired affect.

Are you using Inbound DID or Inbound CID rules?

 

[sac9829]

Yes understand but just wanted to advise for a little extra information on the configuration.

Using Inbound DID as the setup.

Did try an Inbound CID rule for anonymous calls but didn't make any difference as calls still went straight to voicemail.

 

[cobaltit]

So the only thing that makes sense is that you have an inbound DID that has the one behavior and then a catch-all rule on the trunk with the other behavior OR you have a specific CID exception on the extension forwarding rule profile.

 

[YiannisH_3CX]

The routing of the calls does not happen using the Caller ID unless you use CID rules. The routing of calls uses the called number. That should be correct and in the same format as non Anonymous calls. The other thing that could be diverting anonymous calls is an exception. I would use a supported provider as a test and check if you have the same behaviour. Alternatively you will need to use the 3CX Bin log viewer to see what the PBX is doing after the call is received. https://www.3cx.com/docs/3cx-log-viewer/

 

[NoahD]

If it helps, attached should be an extract of the logs from the bin log viewer, showing all calls from 'anonymous'

 

[cobaltit]

What is extension 500?

 

[NoahD]

Sorry, should have mentioned that.

Ext 500 is one of the reception phones and 800 is the ring group that calls both reception phones.

 

[cobaltit]

So from your logs all I see is the call hitting the ring group and only ringing the one extension (500) and then that extension rejecting it. It's not 3CX making that decision. I have you tried replacing that T58 with another phone, even a soft phone to see if it exhibits the same behavior? You mention local settings so any chance you made any changes in the phone? If so I'd factory reset and re-provision from 3CX to see if it does it with a stock config.

 

[YiannisH_3CX]

Add another extension in the Ring Group and remove extension 500 and see if you are getting the same behaviour. You could also direct the call directly to another extension outside the ring group as a test to see if the call is getting rejected.

 

[leejor]

Could it be an option, on that particular set, rejecting the call causing it to go straight to voicemail?

https://www.manualslib.com/manual/1274823/Yealink-Sip-T58v-A.html?page=324

 

[cobaltit]

Could it be an option, on that particular set, rejecting the call causing it to go straight to voicemail?

https://www.manualslib.com/manual/1274823/Yealink-Sip-T58v-A.html?page=324

Absolutely it could be but according to the OP that is turned off:

Edit: Have also checked the phones (Yealink T58) local settings and local anonymous reject is disabled on the phone so shouldn't be an issue.

 

[leejor]

Does an anonymous, non-ring group call, direct to the extension, exhibit the same behaviour? Does this happen with other extensions, or just the one?

 

[sac9829]

Factory reset the phone and this sorted the issue.

The issues appears to have occurred during the last 3CX update and then the upgrade to the supported firmware for the phone.

 

[YiannisH_3CX]

Glad to see the issue has been resolved and thank you for updating the thread with your solution