I've been trying (and trying) to upload some photos to my library and I either get a time-out or the following:
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator and inform them of the time the error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.
My site has been successfully running since October, 2014, so I'm not sure what has suddenly caused this.