I have a xiaomi redmi note 8 and also have a problem connecting the marshall gateway app to the amp code50.
I can only be connected as if I were listening to music, I even tried to connect it with an otg adapter, it works like that, but there are a lot of problems with braking the application? Please if it is possible to solve this problem.
And if I tried all variants except one, and that is to uninstall every marshall application to amplify my Marshall Code 50 Firmware 1.4.4 recognize bluetooth connection from which I can control my installed Gateway 1.5.5 of course not just music to listen to But that I have complete control and whether maybe the problem is that the usb is included in my computer, whether to turn it off because I registered everything else. If anyone can answer all these questions I will be grateful.
Try having ONLY your amp paired with your phone/tab. This worked for both my LG phone and Lenovo tablet.
I stopped bothering with a simple question about an app that certainly works on all phones that have bluetooth.
It is necessary to simply and unpaired all the devices that you have previously paired on your phone with bluetooth, and then slowly step by step follow the instructions.
I wish you all the best. I should have written this earlier but I forgot so don't blame me .
I succeeded like that ... now I don't remember if I restarted the phone, although try that solution when you unpaired all the previous devices that probably bother you because the bluetooth connection happens automatically.