Unstable or no sound

Hi.

I have a trial version of C Pro 8 and VST Connect Pro.

Using a macbook pro retina on both ends. OS X 10, Yosemite.

Using wireless network.

What works:
We have video and connection. I can do all adjusting and configurations.
We see the meters moving in the performer mixer.

Problem:
The audio is highly unstable. Sometimes after a connection, I can hear the performer, but he can’t hear me.
Other times the opposite or no audio at all.
When changing interface inside the performer configurations to Built in audio, we have sound, changing back to the eleven rack, no sound.

Part time solution:
After several times of reconnecting, the sound works both ways.
During that session the sound is ok.
Starting a new session results in the same problem.

What can be wrong, or am I missing something?

Hard to tell. There are several settings to try:
a) raise buffer sizes for the eleven rack. If buit-in audio works but the eleven doesn’t, there is a high probability that either the performance of the eleven or its settings (like blocksize) are causing those hiccups. If it works one time but not another, that may simply mean you are close to the limits.
b) try to reduce upstream settings. With PRO, you can get HD files later, thus minimal settings are sufficient.
c) make sure to have no other programs or background processes which may interfere either networking or audio processing.
d) wireless may be a challenge, so if dropouts occur during recording, you may want to raise the VST Connect “Remote Latency” value, for instance to 1.5 or 2 seconds
Hope that helps.

I’ll second increasing the “Remote Latency” value. I have a residential cable Internet service with 100Mb down and 25Mb up. On a Saturday when all of my neighbors seem to be using their connections, 1.5 to 2 seconds is needed to keep the lights “green.” Also, any competing network activity (Netflix, online gaming, etc.) sharing your network or the remote user’s network can have a big impact.

Lastly, if you can, go for end-to-end wired network connections instead of wireless. Wireless can move a lot of data nowadays, but the latency is 3 to 5 times higher compared to a wired connection.

Ok.

Have tried all your advices with no happy ending.
Any more suggestions?

Not from the distance. You may want to look at the Activity Monitor to see where resources are hitting limits:
/Applications/Utilities/Activity Monitor

In any case, as said, if it works with built-in HW, it must be the Eleven…