Hi there!
In the variable assignment component, the screenshot seems to show a pipe character "|" at the end of the variable name. Can you confirm it? In that case you need to remove that character from there.
Take a look at the following article to understand how to troubleshoot your app:
http://www.3cx.com/blog/docs/troubleshooting-vad-applications/
Following that guide you should be able to check the logs and see what's exactly causing the problem.
Hope the information helps and do not hesitate to contact us again if the problem persists.
Kind regards.