Mango
05/28/2026, 9:26 AMChiranjeet Mishra
05/28/2026, 9:56 AMACaa358e53e6fe124dc0f02fe24d295854. When calls fail at that stage, the concurrency counter increments but never decrements, which is what caused it to get stuck at -1.
To prevent this from happening again, we'd recommend checking the credentials (Account SID / Auth Token) on that Twilio account, as they appear to be invalid or expired. You may need to rotate the auth token and update it on the affected phone numbers in your Vapi dashboard.
Let us know if you run into any further issues!