Report on service very slow for some users

Hi,

I have a report that works fine on desktop. It extracts its data from a dataflow, so no SQL connections.

When I publish it, it works fine for me and other users, loading the whole thing in seconds . But for some other users, it takes 3 minutes to do so. We are doing it at the same time, and all based in London. 

Why does that happen? is there anyway of fixing that? We don't have premium capacity, could that be the cause?

Any help is appreciated, we are almost giving up on Power Bi as our BI solution because of issues like this.

Thanks

Lucas