Strange I'm the same issue as you, it was fine until 6-7 mins then suddenly lost power and speed but the Bluetooth is still connected

Same issue 

after 15 to 20 minutes, lost power and speed, but Bluetooth still connected 

i am using iPad pro

are you using it with big ring front and middle of rear? with small ring front (so with slow rear wheel speed) but with higher power the Flow is overheating (and in this case the electronic shuts down), the inbuilt cooling is insufficent . try to cool it with a fan directly , but avoid the small ring front (yes, i know, on big ring the whole unit is much louder, but it is what the Flow can do, it is a ultra-low budget model, better to sell , or using only as a bike stand...)

Thanks Luko 

i will try the fan and the big gear front ( I always ride in a small gear)

most of the time, I got the problem when I uphill like the Ven-top and alpe the zwift  ( after a few time)

like, we are in summer here, that is became hot in the room and this year is very , very humid. ( do not have a choice ride inside because some injuries)

regard

Yes, unfortunately in Zwift You need to decrease the trainer difficulty settings to the lowest value (10-20-30%, especially on Ven-Top and Alpe) for climbing on big ring with slow ingame speed (but fast rear wheel speed in reality) , otherwise the Flow gets overheated within 10-15-20mins (depending on watts). If You have 3DPrinter, You can print an adapter and attach an extra 80mm cooler to the side of the Flow and it will help a lot:

www.thingiverse.com/thing:4757313

Wow , thanks Luko 

friend of mine ha e a 3D printer

thanks a lot