This means that there is a communication problem with the watch and the phone.
Try restarting the phone, or closing Rain Parrot using the task switcher.
Also try opening the watch app before the app, and vice-versa. Note that you will need to fully close the app before it will try re-sync, which may mean restarting the phone.
It's a fiddly problem but it is resolved with a bit of playing around to get the phone to talk to the watch.