I have a similar app (actually 2) that needs internet connectivity while opening a session, and I am using Android. In the past there have been connectivity issues. One time it fixed itself after I updated the Android OS. Another issue can be that your phone may be connecting to a network and not allowing the OTR software to connect, some apps need to connect to your phone with WIFI and can't do it if you are connected to another network. Did you try going into your network settings and looking for the app?
I also see on their site they are working on V2 for Android, maybe that will help. Unfortunately problems can also arise if your phone or tablet is too old for the latest OS updates.
I'm not too crazy about these internet based automotive apps but the ones I have were cheap, less than $70. For what OTR charges you should get pretty good support.
Brian, 2011 Winnebago Via Class A on Sprinter Chassis
2000 Jeep TJ toad