Troubleshooting

Calls drop or cut out mid-call

Short answer

Every dropped call ends with a BYE, and the call's SIP trace in the Enfonica Console shows which side sent it. If calls drop at the same point every time, such as 30 seconds after the answer or about 15 minutes in, the time points to a specific cause. If calls drop at random, look at the side that sent the BYE.

Applies to
Cloud SIP, Phone Numbers
Works with
Any SIP PBX or SBC
Who can do this
Whoever manages your PBX and your Enfonica project

Check for a known incident first. If there is one, we're already working on it, and there's nothing to change on your side.

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On this page
  1. What are you seeing?
  2. Calls drop at the same point every time
  3. Calls drop at random times
  4. Calls stay connected after the other person hangs up
  5. How do I see who ended the call?
  6. What to send us
  7. Related

What are you seeing?

Calls drop at the same point every time

Note how long the dropped calls lasted, and then match the time to one of the following causes. A fixed time points to a timer, and each timer has a known cause, so this is the quickest kind of drop to trace. For the exact time, look at the call's Duration and Timeline in Cloud Voice > Calls.

About 30 seconds after the call is answered

When a call is answered, the answering side sends 200 OK. The other side confirms it with an ACK. If the ACK never arrives, the answering side keeps resending 200 OK and ends the call after about 30 seconds.

Check

Open the call's SIP trace. This is the cause if the same 200 OK appears again and again with no ACK in reply, and a BYE follows about 30 seconds after the answer.

Fix

Allow both of Enfonica's signaling addresses, 34.87.239.197 and 34.87.254.143, in both directions, in the firewall in front of your PBX (phone system). Then turn off SIP ALG on your router. SIP ALG is a router feature that rewrites SIP messages as they pass, and it can damage them.

About 15 minutes in, on calls through your PBX

Some PBXs refresh each call at a set interval, such as every 15 minutes, by sending a second INVITE (a re-INVITE). If the PBX then sends a malformed ACK, Enfonica can't route it and ends the call about 30 seconds later. For example, the ACK might be addressed to a different place than Enfonica asked for.

Check

Look at when the calls drop. This is the cause if they drop at about 15 minutes and 30 seconds. In the SIP trace, your PBX sends an INVITE about 15 minutes into the call, repeated messages follow, and then the call ends.

Fix

Change your PBX or the network in front of it. Turn off SIP ALG on your router. Then look in your PBX's trunk settings for session timer or re-INVITE options to change. Your PBX vendor can confirm which setting applies. A packet capture from the PBX during a 16-minute test call gives them what they need.

Exactly 4 hours

Every call through Enfonica can last up to 4 hours from when it starts, including the time it rings. Then the call ends.

Check

Look at the call's Timeline. This is the cause if Ended is exactly 4 hours after Started. The Duration is a little less, because it counts from the answer.

Nothing is wrong. For a call that needs to last longer, such as an open line between two sites, set it up to redial when the call ends.

Calls drop at random times

A random drop always ends with a BYE from one side of the call. Look at the side that sent it. To find the BYE, open the call's SIP trace, as described in How do I see who ended the call?

Your PBX, dialer, or contact center platform ended the call

Check

Find the BYE in the trace. This is the cause if it goes from your system toward Enfonica. Select the BYE to see its Reason header, if it has one. The header often names the cause. For example, Reason: SIP;cause=480;text="WebRTC disconnect (iceIdleDetection)" from Genesys Cloud means that the agent's browser or device lost its connection to the platform.

Fix

Check your system's logs for the time of the drop, or send the Reason to your platform's support team. If the drops follow one agent or one site, the cause is usually that person's device or internet connection.

The other person, or their network, ended the call

Check

Find the BYE in the trace. This is the cause if it goes from Enfonica toward your system. Enfonica passes on the hang-up it receives from the phone network, so the call ended on the other person's side or in their network.

Fix

Look at how often it happens. If it's one call, the other person most likely hung up or lost signal. If drops keep happening with the same number or network, send us two or three recent examples, and we'll check them with the carrier.

Calls stay connected after the other person hangs up

The other person has hung up, but your phone, PBX, or dialer still shows the call. The SIP trace shows whether Enfonica told your system that the call ended.

Your system received the hang-up but didn't act on it

Check

Open the SIP trace. This is the cause if Enfonica sends a BYE and your system replies 200 OK, which means that your system received it.

Fix

Look between your PBX or dialer and the agent's phone. Check your system's logs for that call. Also check the router between them. A router that runs short of connection memory (its NAT table) can lose messages inside your network.

The hang-up didn't reach your system

Check

Open the SIP trace. This is the cause if Enfonica sends a BYE several times with no 200 OK in reply. Your firewall is likely dropping messages from one of Enfonica's signaling addresses.

Fix

Allow both 34.87.239.197 and 34.87.254.143 through your firewall, in both directions. If the trace shows no BYE from Enfonica at all, send us the call, and we'll look at it.

How do I see who ended the call?

The side that sent the BYE ended the call. To find the BYE in the call's SIP trace:

  1. In Cloud Voice > Calls, find the call and open it.
  2. Under SIP Insights, select View SIP trace. The trace draws the call as a ladder of messages between columns, one column per system.
  3. Find the BYE near the bottom. Its arrow starts at the side that ended the call.
  4. Select the BYE to see the full message, including any Reason header.

Enfonica's column is labeled with one of its signaling addresses, 34.87.239.197 or 34.87.254.143. The other column is your PBX, dialer, or platform. To learn more about reading a trace, see Find a call and read its SIP trace.

What to send us

Include these and we can find the call straight away.

  • The number that made the call and the number it called, in full international format (for example +61255501234).
  • The date and time of the call, with your timezone.
  • Whether the call was inbound or outbound.
  • The call ID, if the Console shows the call.
  • What happened: an error message, silence, a busy tone or a dropped call.
Contact support

Our support team are telco specialists, backed by the engineers who run the network.