1. Ensure that your iOS device and your Mac are on same wireless network.
2. Check that Rowmote Helper is installed and running on the Mac to be controlled. If controlling a Class Apple TV, please see the installation instructions page.
3. Verify that your network allows Bonjour traffic. Some public, ‘guest’, and semi-public (e.g. corporate) networks don’t allow Bonjour traffic. Bonjour is the technology which Rowmote and other applications use for zero-configuration networking.
A free way to test this is to try out Apple’s free Remote software for controlling iTunes. If that works, then Bonjour works on your network. If it doesn’t work, try creating your own network. Ask your network administrator to enable Bonjour traffic if this turns out to be the problem.