I can't get the android mobile app on my samsung phone or samsung tablet to pair with Videostream on my iMac. I can cast video from the iMac directly from Videostream. I can cast and remotely control video from the iMac using both android devices via ES File Explorer. In Videostream when i click on Add computer after a few seconds its says cannot find any computers even though all the devices are on the same network and communicating using other applications. I tried deleting and reinstalling Chrome and the extensions on the iMac but made no difference. Videostream apps on the Android devices are paired fine with my Windows 7 laptop also the same network.
How to proceed?

Thanks - Paul