If you are using the Android app version 3.1.1026 or the one from google play, there is a conflict with the newer BMS firmware version 2.1.
The BMS does not have a password function, but the app still expects it to be there. It will send the blank PIN (000000) and get a negative response from the BMS, and the app gets stuck in this loop.
This has been resolved in the iOS app.
We are also coming out with our own new android app soon that will solve this problem.
For now, you can try the older version of the android app 3.1.1015, or try the iOS app, or the desktop app via USB. Links to these applications can be found here: https://overkillsolar.com/support-downloads/
If you need to use the USB desktop app to fix this, you can email firstname.lastname@example.org and request a free USB module.
Note that the existing Android app version 3.1.1026 will never work with BMS firmware 2.1 even if you reset the password.
We apologize for the inconvenience.