I made this comment in response to another query and thought it would useful as part of the general forum...
Been following the comments about Bluetooth for a couple of weeks since I have been having the same problem. What I discovered is that the problem is not the amp but my phone. For all intents and purposes, the amp is just a dumb device that happens to have a Bluetooth connectivity board or circuit built into it. The primary connection device is the users phone, tablet, whatever that has the Bluetooth application. Anyone using a Bluetooth speaker should know and understand that the speaker has no application, just an ON/OFF switch and a Bluetooth circuit. It's the phone that makes the connection. So in my case, it was the phone that dropped or lost the connection to the amp. There was no way I could reconnect, even after shutting everything down and rebooting. Going through the Gateway app on my phone wouldn't work and the blue light on the amp would blink continually.
What I then tried was turning off my Bluetooth on the phone, reactivating, and getting the app to pair up again to the amp. Problem solved.
It's possible that all the wi-fi items I have in the house and garage are confusing the phone and Bluetooth but I haven't troubleshooted that as yet. I have found a simple work-around that, I agree, is less than ideal but gets me using the amp the way I want. I don't disagree with what users are saying but I also think that not every fault lies with the supplier. Perhaps a reasonable challenge to us users would be... if any musician is a programmer or electrical engineer then offer some assistance. I have yet to find any innovator who can design for every nuance we currently experience in this tech world. Also if anyone has another, better work-around then please submit to this forum.
I truly do do hope Marshall is working on the App and Bluetooth issues. This will be a fun amp if they get it working. It’ll be perfect for my needs.