Hello Support Team, I am experiencing a persistent issue where my Vapi number, sourced from Zadarma, receives inbound calls successfully, but all outbound calls fail. I have performed extensive troubleshooting and require assistance checking the SIP logs, as the problem appears to be a final rejection from the Zadarma side. Here are the details of my setup and troubleshooting steps: Credential ID (The one that fails): aa20fed9-32c6-4b3b-898d-b3fef49c83a3 Credential Name: Zadarma-NoPlus SIP Account Type: Main Zadarma SIP Account (PBX has been disabled). Authentication Used: Main SIP Login (850561) @ sip.zadarma.com. Troubleshooting Status: Authentication Fixed: The Vapi Private Key is confirmed to be working. Trunk Creation Fixed: The SIP Trunk Credential (aa20fed9-32c6-4b3b-898d-b3fef49c83a3) was successfully created and is linked to the phone number. Number Format Tested: I have tested two versions (outboundLeadingPlusEnabled: true and false). The current linked version is false. Request for Logs: Please review the SIP logs for the most recent failed outbound call attempt from my number using the Credential ID aa20fed9-32c6-4b3b-898d-b3fef49c83a3. We need the exact SIP rejection code that Zadarma is sending back (e.g., 403 Forbidden, 603 Declined). This is the last piece of information required to complete the fix. Thank you for your help!

Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team

If you’re open for a quick chat we could schedule a time to work on this together..

I'm in

I’m considering we schedule a meeting for around midnight when I would most likely be available or better still add me to your Vapi and zadarma workspace so I could handle the issue from here..

Are you trying to do multiple outbound calls on Zadarma? They may have limited the login concurrency on your user.