I wanted to reply as I had the same issue. I guess the best way I explain it to myself is that the IPad and the FX100 are Bluetooth paired, but the Amplifi IPad sofware doesn't think so between the pedal board and the IPad.
The following solved the problem for me.
- Update firmware if you have the opportunity. If you can do a factory reset to the previous version and go through the firmware update this at least would reset thing
- Successful calibration - I think this is what solved the issue for me. Make sure that you follow the steps correctly.
- Close the Amplifi app (see below)
- Unpair the FX 100 with the IPad
- Re-pair the FX100 with the IPad
- Restart the Amplifi app
I hope that this helps.
Note that you MUST close the Amplifi IPad app to reset it so that it looks for the pedal board again, as presssing the home button doesn't close apps (they are terminate and stay resident programs -> i.e. stay in memory -> think alt tab on your computer). To close an app, double tab the home key, find Amplifi and slide it up to the top.
Please forgive me if you already knew about closing apps, but in case you didn't I want you jamming ASAP