Inbound Calling Sometime Results in 'the dialed number is not valid'

[Benjamin Williams]

I have a very intermittent issue that I have been troubleshooting for over a week now - I have one customer (out of many) that is currently experiencing a problem with random inbound calls; out of maybe 100 - 150 calls per day, 5-10 calls are problematic; that is, when an outside party attempts to dial my customers primary number, they receive the message, 'The Number dialed is not a valid working number' (or something along those lines). If the external party calls the number back, they can normally get through (sometimes it takes 3-4 attempts to make the connect however).

Tasks that have been completed during the troubleshooting process

- I have requested several examples from my customer based on the inbound-callers phone number, time of call, etc., It's been comparable to pulling teeth but I have been able to manage to obtain a few examples.
- Ran Wireshark packet-captures on the PBX to determine if these calls are actually hitting the PBX (they are not, whatever details are being captures within the Call Log within 3CX match up to what I am seeing within the Wireshark captures.
- I carried out an extended ~24hr ICMP test to check and see if the customers WAN connection could be flapping (I did not observe any loss of connectivity/packets during my testing)

I have never been able to recreate the issue since the problem is so hit and miss; each time that I have called this office, my calls goes through without issue. (as most calls do).I have called the office multiple times throughout the day/week (for testing purposes) and I always can get through. I do know that there is a problem however, just not sure where exactly its occurring.

Note: My customer is using a SIP provider that is actually being managed by another MSP, however, I am in the process of moving them over to our SIP provider (the process of porting the numbers is already moving forward). Until this process completes however, I was hoping that somebody out in 3CX-land might be able to provide some additional pointers/assistance with what else I might need to look out for.

 

[leejor]

when an outside party attempts to dial my customers primary number, they receive the message, 'The Number dialed is not a valid working number' (or something along those lines).

This sounds to be a message from a provider, be that the originating, or terminating. Unless you can find a log of the incoming call , in 3CX, it would appear, off-hand, as a provider issue (or callers dialling incorrectly). If it is callers from a specific provider, or group, then it may be a porting issue. See if it can be duplicated, and get your provider involved.

 

[ChrisC_3CX]

@Benjamin Williams
Since you've already confirmed that the calls are not hitting your PBX the only thing you could check yourself is confirm they are not hitting the firewall on your PBX site either. If nothing reaches the firewall either then your best bet would indeed to, as leejor put it, get your provider involved as well. I do not know if this is worth looking into just yet though since you are moving to another provider which may rid you of the issue altogether.

 

[Benjamin Williams]

Thanks to both of you for providing a response/feedback. I will migrating this customer over to a new fiber link sometime later this week (currently, they are using a traditional cable modem for their internet needs). I am hoping that this change may introduce some added benefit based on these intermittent problems that we've been bumping up against.

I am awaiting for the current SIP provider to process a CSR so I can start the actual port process; they are dragging their feet.

Thanks again for your assistance.

 

[ChrisC_3CX]

@Benjamin Williams

You're very welcome!

Do let us know how it goes!