1. Do you experience this problem if you were using SMSLISTO directly?
2. Is there a STUN server setup up on your SPA (see
Setting Up SPA3102 - Voxalot FAQ )?
3. What is the setting of NAT Symmetric handling when you log into VoXalot?
4. What is the setting of the Optimize Audio field for your SMSLISTO setup (Optimize Audio can only be set to Yes, if NAT Symmetric has been set to NO)...