Hey all — looking for some help.
I’ve been successfully using Vapi with Make.com to build an automated outbound calling system (still in testing phase). Everything was working smoothly until recently — now I’m hitting a wall.
🛑 Issue:
Every outbound PSTN call attempt now returns a [400] Bad Request from the Vapi module
Nothing shows up in the Vapi call logs (not even failed attempts)
I tested with both old and newly created Vapi phone numbers
Tried multiple phone numbers that previously worked fine
Setup hasn’t changed — same scenario, same assistant, correct E.164 format
✅ Notes:
The rest of the Make.com scenario runs perfectly
It seems like Vapi is rejecting the call creation before queuing/logging
Already sent an email to support, but wondering if anyone else has hit this before?
Any ideas what could cause this? Rate limit? Carrier route issue? Assistant or number block?
Appreciate any insight 🙏