At the completion of a painless Skype for Business in-place upgrade I found that outbound calls of any modality would fail. Looking in to the server logs I found the error “500 Server Internal Error” and “Request handler threw an exception”. I also noted that the server referenced was AudioCodes SmartTap – http%3A%2F%2Fwww.audiocodes.com%2FSmartTap%2FLync2010
You can also see the same AudioCodes reference in the monitoring server call detail records under the user agent.
While I suspected SmartTap was causing the issue, not having come across it before I was a little stumped. After many hours I reached out for help, and fellow MVP’s Michael LaMontagne and Adam Gent pointed me to the solution; uninstall the AudioCodes SmartTap service from the Front End server. Of course if you need this service, you’ll probably need to talk to AudioCodes and see if there is an updated version, or maybe try a re-install. In my case this was a legacy service and was no longer in use.
Hope this saves someone time while burning the midnight oil.