Failed to connect to istance

Would you be able to post your system specs, and what kind of connection you're playing on? It seems most likely that something with your connection is causing a problem, but then it's very odd that it only just started happening with 0.9.11!

It sounds like your connection is having a problem with a specific server - That may be something your ISP needs to investigate, if you can find the exact address of the server with the problem? This can usually be found in the Log files in your Path of Exile folder.