Xiaomi wifi repeater question

[n.i.k.t.o]

Dear TELLO pilots,
Yesterday i finally bought the Xiaomi Wifi repeater.
I tested it today on a field at nearly 50 m from train powerlines.
I tried to fly it with and without connecting the repeater and i have observed that there was not too many difference in distance, just a bit in the video quality. But, when i reached a distance of nearly 70 m with the repeater, i lost controls and the FPV of my drone, also a "strong wifi interference" message appeared meanwhile the app was showing 5 bars of signal,but when i went to the same distance without the repeater, i had just freezed FPV but i still could control the drone. What could be the problem?
Just for information: i am using Ryze (but soon i will by the Tello FPV app), my phone is a Xiaomi Redmi 9. I was holding my power bank straight vertical and the repeater was folden at nearly 30° relatively to the power bank.

So what could be the problem?
Thank you in advance.

 

[Hacky]

When you saw 5 bars on the phone, then it was the signal strength between phone and repeater. So the problem was the connection between repeater and Tello.

I am not sure, what you mean with

...power bank straight vertical and the repeater was folden at nearly 30° relatively to the power bank

 

[n.i.k.t.o]

Good morning,
By this sentence i meant that the repeater was at 120° relatively to the ground. It was aways facing the drone. Sorry, I have written it in a stupid way.
And also thank you very much for the reply, i will try to reset the repeater.
Have a nice day)