31481: Call/Transaction Does Not Exist

31481 means the call or transaction you are referencing no longer exists. For outgoing calls, Twilio does not assign a CallSID until the accept event fires, and a Call can move to closed after the remote end cancels it.

• You tried to read or use an outgoing call's CallSID before the accept event fired. For outgoing calls, the call may not have a CallSID until then.
• The call was canceled by the remote end, which transitions the Call to closed.
• In a Voice SDK app, the CallInvite object was released before the underlying signaling connection finished processing the invite lifecycle.

• Wait for the outgoing call's accept event before you read or rely on CallSID.
• Treat cancel as terminal in your call flow and stop any follow-up actions once the call has been canceled or disconnected.
• Keep the CallInvite object alive until the invite is accepted, rejected, or canceled.

• Error and Warning Dictionary
• Voice JavaScript SDK: Twilio.Call
• Voice Android SDK Changelog