Does the phone or tablet you are using have internet access? The sign in process and telepresence runs over the internet using WebRTC. The ROS connection is not used for this project.
I've heard of people having this issue. Sometimes it gets stuck signing in. Try rebooting the device and see if the works. If not let me know what kind of devices you are using (model and version of Android).
You can get it herehttps://play.google.com/store/apps/details?id=com.tesseractmobile.pocketbot
Here is the arduino library. It also includes example code. https://github.com/frankjoshua/PocketBot
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