Two of my agents stopped getting user audio and keypad inputs

Support Help
21

Hello @yasser.santiago glad the picture clicked. Two things to flag before you act on the ES/DE plan:

**1) On the diagnosis framing.** STIR/SHAKEN attestation is a real factor on cross-border forwarded calls and likely contributes to caller-side hesitation, but it isn’t the full story for the silent-RTP pattern we saw today. Your BYOC DID +17865036901 is also a US number receiving the same cross-border Aircall forwards (same Failed-A attestation pattern would apply), yet it captured audio on 14 of 16 calls today while +17862203563 captured audio on 1 of 16. The variable that flipped the outcome was the trunk / Retell-managed Twilio subaccount carrying that DID, not the attestation status. So any fix that simply moves you to a different trunk has a strong chance of working even if attestation behavior is unchanged.

**2) On the procurement question.** Retell’s directly-purchasable DID inventory in the dashboard is currently US/CA only — there isn’t a flow to buy Spanish or German numbers natively in Retell. To get EU-local DIDs attached to your agents, the supported path is BYOC (bring-your-own-carrier) SIP-trunk import:

  • Obtain the ES / DE local DIDs from a carrier that sells in those countries (your existing Aircall account may be one option if they expose SIP trunking on those DIDs; otherwise any in-country SIP carrier).
  • Import the DIDs via custom telephony into Retell (same mechanism you’re already using for +17865036901): Custom Telephony Overview - Retell AI
  • Forward Aircall traffic into the imported DIDs (or, if Aircall provides the DIDs themselves via SIP, skip the forwarding step entirely).

For your two priorities:

  • Bypass the affected Retell-managed Twilio subaccount: yes — anything routed via BYOC sidesteps it, which is exactly the pattern your healthy +17865036901 already demonstrates.
  • Preserve original caller ID: BYOC forwarded calls preserve the original E.164 in the SIP From / P-Asserted-Identity / Contact headers — we confirmed this in your PCAPs earlier in the thread. No need to mask the customer’s number to make BYOC work.
  • Avoid cross-border attestation friction: keeping the call in-region (EU caller → EU local DID) plausibly removes the cross-border STIR/SHAKEN failure mode, but the exact outcome depends on the EU carrier’s signaling. Worth validating with one test DID before migrating volume.

Two things to confirm carrier-side before you commit:

  1. Whether Aircall (or your chosen EU carrier) sells SIP trunks on ES / DE numbers, not just PSTN forwarding — SIP-native is required for BYOC import into Retell.
  2. The local carrier’s documentation requirements for issuing ES / DE DIDs (proof of address, in-country presence) vary by country and are managed at the carrier, not at Retell.

Thank You