Apologizes, I missed the last bit of your original post.
Regarding the extra slash though, it doesn’t seem to be an issue when querying the controller. In other words, for me both /js/?pw and /js?pw work and return the expected reply. Therefore, I am not even sure if that is the issue.
If you don’t mind, the best way to identify the error would be to debug using Chrome. You can plug your phone into your computer using a micro USB cable and change the settings to allow USB debugging. You might need to unlock the developer menu to accomplish this which can be done by tapping the build version in the about screen 7 times (if memory serves). Once this is completed, you can open Chrome and navigate to: chrome://inspect.
You should see your phone listed (when the app is open) and it will allow you to “Inspect” it. Here you will have access to the web developer console which allows you to look at the network traffic tab and the console in hopes of identifying the error.
Would you mind trying the above steps to see if you see any errors or warnings?
Thanks!