I can see the distance and my position, not the route

I have tried the caynax sports tracker for the first time with an one hour bike tour. It showed me on the map where I was, but not the route I had already cycled. And after the tour I could only see on the map the farthest point I have reached, not the way I have gone.

What did I do wrong?
Thank you

Wow. This is really unusual. What device do you use?

I am using a Samsung Galaxy A40.
After trying some things it works better now. I had the cell phone in my purse before so I think it didn’t receive the signal.
If I put it on top of the bike basket it works most times that the cycled way is shown. But it still looses the signal pretty often. If I often open the app and press the radio (?) button on the upper left, it connects again.
But that is not very handy to have to do that again and again. I want to try a bike bag for the handlebar so that I can do that while I am going.
Did anyone else experience that?