help with location

We finally got Matomo going (thank you Lukas!), but still have a serious problem in the sense that it doesn’t determine the location of our visitors. Everybody seems to be located in San Jose, USA, and have the same IP address. As this location is the location of our server, we asked them if there was a problem on their side. the answer was pretty swift, and not so friendly.
“it appears that the original issue reported is related to a 3rd party application, for which we are unable to offer additional technical assistance”
So, has anybody any ideas how we can avoid the whole world population being located in San Jose?