Thanks for getting back on this. I am seeing a few different messages; "secure session denial" and "unable to connect to reader".
The reader is paired with the phone via the bluetooth on the phone. I only discovered how to do this by accident when downloading the reader app for the third time, it mentioned to press the power button on the reader till lights flashed orange and place it next to the phone. This advice doesn't seem to appear anywhere on the square website, at least I couldn't find it.
I have spent over a half a day trying to get this thing to work and am ready to give up. I have followed every instruction on every website I can find and rebooted, re-downloaded, turned off, refreshed etc etc countless times.
I have gone into phone settings and square reader has permissions (is that what you mean by developer options?)
Very frustrated now.
