Tello+T1s+Tello app+ no previev after connect

[ophiel]

Hello.
I have a problem with preview from my tello.
I have a OTG cable and use a Tello app.
Controller T1s.
Always I connect with OTG and I watch a screen from Tello in my phone.
But for some time when I connect controller preview are black screen.
I remember I connect T1s with OTG cable but now connection is only with bluetooth.
Can anybody help me?