Common voice call issues

Calls can fail for a lot of reasons. Here's how to read the most common ones.

Call was answered and hung up immediately

• Sometimes legitimate (wrong number, not interested)

• If this happens across many calls, it likely means you've been mislabeled as spam — see our article on spam labeling

Call couldn't connect / busy tone / no audio

• Usually a temporary network issue on the recipient side

• Usually resolves on retry

• If persistent across many recipients, contact support

One-way audio (one side can't hear the other)

• Almost always a firewall or network routing issue on the calling side

• Contact support with the call timestamp

Anonymous / private number calls blocked

• Some recipient carriers block calls without proper caller ID

• Make sure CNAM is enabled

Call to a number that doesn't exist

• The dialed number is invalid or has been disconnected

• Clean your calling list — this counts against your reputation

When to contact support

• Failure rate above 15% on a single campaign for more than an hour

• Any persistent one-way audio issue

• Any failure affecting inbound calls (customers can't reach you)