[Solved] How to pair the Sonoff TH10 and what to do to make the relay active?

Hello
I have purchased a sonoff TH10 and for the love of the world I cannot pair it.
Maybe out of 50 times of pairing I managed once but there was a device off line all the time. So I deleted it and wanted to pair it again with my phone and was unsuccessful.
ewelink software on android latest.

Anyone help me pair it and so that once paired there is no device off line?

What hardware I have:
Phone: Xiaomi Redmi 9
Router: huawei EchoLife HS8145V from internet provider.

Added after 1 [hour] 14 [minutes]: .

I have already paired successfully only now what to do so that there is no device off line?

Instructions. Link .

Problem solved. The reason was one big letter in the password which the phone automatically changed on its own and I didn't notice it. Therefore, when I managed to pair it was still a device off line. The manual also came in handy.