In an instance of official Zotero, I'm seeing the Preferences -> General -> "Update" button change to "Error" when attempting to update styles and translators.

An attempt to submit the error report also reported "Invalid response from server".

Maybe there is something funny at this end, but I can't think of what it might be.

Here is what looks like the relevant part of the trace in Preferences -> Advanced.

(Not sure if this is enough info; and sorry for the clutter.)

---

version => 4.0.24.1, platform => Linux i686, oscpu => Linux i686, locale => en-US, appName => Firefox, appVersion => 34.0.5

=========================================================

(5)(+0000000): SELECT version FROM version WHERE schema='repository'

(3)(+0000000): Checking repository for updates

(3)(+0000043): Cached 15 styles in 42 ms

(3)(+0000000): HTTP POST styles=%5B%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fnature%22%2C%22updated%22%3A1403376388%2C%22url%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fnature%22%7D%2C%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fcell%22%2C%22updated%22%3A1359205598%2C%22url%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fcell%22%7D%2C%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fbps%22%2C%22updated%22%3A1409385568%2C%22url%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fspringer-socpsych-brackets%22%7D%2C%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Famerican-anthropological-association%22%2C%22updated%22%3A1348751198%2C%22url%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Famerican-anthropological-association%22%7D%2C%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fchicago-fullnote-bibliography%22%2C%22updated%22%3A1400144573%2C%22url%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fchicago-fullnote-bibliography%22%7D%2C%7B%22id%22%3A%22http%3A%2F%2Fwww.zotero.org%2Fstyles%2Fmodern-hu... (2958 chars) to https://repo.zotero.org/repo/updated?last=1417305600&version=4.0.24.1&m=1

(2)(+0000777): Invalid response from repository