Intermittent silent/blank voicemail

[TLCtech]

• 3CX Version, Enterprise Annual 18.0 Update 2 (Build 314)
• Server OS, Debian GNU/Linux 10 (buster),4.19.0-18-cloud-amd64
• 3cx hosted
• Provisioning Method: Cloud?
• Trunk Provider: Call Centric
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

At first, the blank voicemails came in from one number. We are up to 4 different numbers coming through, leaving voicemails, and nothing actually saves. Its just silent audio. Not just attached to the email, but when you listen in the app or in browser, most are 2 sec long and silent. The first one that came through was 1min long and we confirmed that one was a left voice mail that we never got. Any idea what this might be?

 

[VasilisV_3CX]

Hi @TLCtech,

If you make a test call internally (from any extension to the extension that received the blank VM) and leave a VM, does it leave a voicemail?

If you make the same text externally from a cell phone to your extension, and leave a VM of say, 10 seconds, does it record properly?

 

[TLCtech]

Hi @TLCtech,

If you make a test call internally (from any extension to the extension that received the blank VM) and leave a VM, does it leave a voicemail?

If you make the same text externally from a cell phone to your extension, and leave a VM of say, 10 seconds, does it record properly?

When I or anyone else tries, there are no issues. Not internally, not externally. Its very intermittent. I think we might have 8 calls like this since October.

Here is the latest one.

 

[VasilisV_3CX]

Hi @TLCtech,

Has anyone in the company received calls from the blank VM caller? Can you confirm that these voicemails aren't in fact just someone hanging up after 2 seconds of waiting and that they were longer voicemails?

 

[TLCtech]

Yes, we routinely get calls from these folks. Most are clients of ours. The latest voicemail was 2 minutes long and we identified the call as a client's.

 

[VasilisV_3CX]

Hi @TLCtech,

This is an interesting bit of added information you've provided. 2 minutes happens to be the maximum duration for voicemails before they're cut off. To be sure, you'd need to contact a 3CX Partner to assist you with a packet capture to listen to the audio and see if the audio is the same in the packet capture as it is in the voicemail. This can point us towards a possible issue where, for example, for some reason your provider is not sending audio or a bye message to tear down the call or perhaps shed more light on the issue.

For now, I suspect that the calls are in fact blank but without a capture I can't be sure. Looking forward to your update.

 

[TLCtech]

Hi @TLCtech,

This is an interesting bit of added information you've provided. 2 minutes happens to be the maximum duration for voicemails before they're cut off. To be sure, you'd need to contact a 3CX Partner to assist you with a packet capture to listen to the audio and see if the audio is the same in the packet capture as it is in the voicemail. This can point us towards a possible issue where, for example, for some reason your provider is not sending audio or a bye message to tear down the call or perhaps shed more light on the issue.

For now, I suspect that the calls are in fact blank but without a capture I can't be sure. Looking forward to your update.

Would a packet capture be necessary if the instance is cloud hosted on a 3cx owned server? We have called these clients back and they said they DID leave a voicemail. If that helps at all. I just know that getting a partner to come has been a hard sell for my client in the past.

 

[TLCtech]

More info: I think this less to do with the VM and more to do with blank audio coming in. When asked, the front desk said they do get calls with no audio on occasion. So you might be correct that there could be an issue with the phone provider.

 

[VasilisV_3CX]

Hi @TLCtech,

Yes the packet capture would help regardless as it will tell us if the issue is happening on the PBX or coming from the provider. I'd suggest following the previous advice mentioned so we can get to the bottom of this asap.

 

[jessy.paconnect]

@VasilisV_3CX To add to this, we do experience this across many of our clients. Voicemails will be 10, 30, or even up to a minute long with nothing in it and no transcription. The client will call the customer back and they inform them that they did in fact leave a voicemail. This has been happening for years at random. Its rare but it happens. Capturing voice packets would be impossible due to how rare it is.