OpenVPN dead spots

[Karl_Yealink]

1. Each call, the problem will occur?
2. During the dead spots, the phone can't hear the other side, and the other side also can't hear?
3. When will the phone face the dead spots?
4. The phone version? How many phones?
5. If you don't use the VPN, will the phone work well?
6. Please help us to capture the trace files. Please refer to FAQ: http://support.yealink.com/faq/faqInfo?id=311
We can check something from them.
You can send the files to me via email(karl@yealink.com) and copy this post, I will check and give you respond.