Hi I have the same issue - I am working for a client located in Spain - the root cause — the A-law / mu-law codec mismatch explains everything we've been experiencing. Summary of what we've already tested and ruled out: - Telnyx network quality is perfect: Jitter 0.00ms · MOS 4.50 · Packet loss 0% - Codecs tested on Telnyx side: G711A only, then G711A + OPUS → same issue - Noise suppression: tested disabled, inbound only, both → same issue - Media region confirmed via websocket URLs: all 3 of our last calls routed through aws-us-west-2-backend-production1.vapi.ai (Oregon, USA) for calls to Spain (+34) ---> How did you solved your problem ? I am using SIPtrunking