Hello, rafaelcsalles.
Do you have the SecureLine - Standalone version?
If "yes", we have to wait Avast to fix the drop down list issue. For now, we're unable to choose the servers that we cannot see.
I suggest you to use the "Tab" key and try to pick Sao Paulo server.
Link to the screenshot: Click here(in my case, i have a monitor with 1920x1080 resolution and i'm able to see/connect "Sao Paulo" server)