I can see the error - your workflow is trying to save, but there's an issue with the credential configuration. The "End Call" node appears to need a valid UUID for its credential ID. The issue: The workflow references a credential that either doesn't exist or isn't properly configured in your VAPI account. Quick question: Are you using the built-in VAPI credential or trying to use a custom credential? If custom, have you created it in your VAPI dashboard under Settings → Credentials first?