A flying saucer shot over mountains in Switzerland

On August 7, 2017, in the afternoon, a grey/metallic flying saucer was photographed over the city of Leysin, in Switzerland. What is it?

Witness report:

The person who did take the picture was walking in the mountains and did take a picture heading north direction lesyn. we discoverd the object when we sorted our pictures. we first did think it's a cloud and decided to zoom the picture. since then we try to discover what it could be. we asked flight controls and local media if there was airplanes or ballons in this region at that time, they answered no.

http://ufostalker.com/sighting/98765, 26th February 2019