The message appears when the speed test is blocked from reaching a test server.
It has turned out to be almost always either Adblock, AdblockPlus or NOSCRIPT
The error message is correct, at least, has been so far: it is always an extension
and whatever extension it is, does not report to what it is doing, just rips a hole
in the browser.
Of course, I'm happy to add an additional error if it turns out to be incorrect.
Are you sure Adblock is disabled? and no other extensions are operating?
by the way I dislike adblock intensely, and not for selfish $ reasons, they filter
javascript and html and CSS using regular expressions (first mistake) and then
rip out anything matching any combinations of letters that were once or are now
used in part of an advertising url, function or style template. In doing so they
constantly break everything. Of course as a user, you just think a site looks
badly formatted, or is buggy, and move on.
thanks
-Justin