When I still had the wp multisite at 3.4.2 version I had this issue. With google chrome browser many times when it was loading my site or a post/page from it it was giving me this message "oops google chrome could not find ....". On Firefox it said "The conection has timed out". The problem with Chrome and Firefox continues at the update on the version 3.5. Which is the reason of this problem and how it can be fixed?