After trying to deploy an application to 3cx, the VAD indicated success.
However, in the windows event log there was a warning stating "Post size exceeded allowed limits".
Basically because I had quite a few audio files, the default max post size of 30MB was not enough and the application had problems.
To fix this add/change this setting in the web.config file
<httpRuntime maxRequestLength="[NUMBER OF BYTES]" />

