Hi, I can help with this. That call.start.error-get-transport usually means Vapi can’t establish the Telnyx call transport, most commonly from a credential mismatch, SIP/Voice Profile routing issue, or the number not being linked to the same outbound profile Vapi expects. Since the call ends instantly with zero duration/cost, it’s likely failing before the call is actually handed off. Can you confirm whether the API key/credential in Vapi was recently regenerated, and whether the assigned Outbound Voice Profile on Telnyx is the exact one tied to that phone number? @Vlad1992