The British Caving Association

If anyone's web site has suddenly started reporting "500 internal server error" this may be due to an upgrade at Apache. Check your error log, via control Panel / Metrics, and you may likely find that your server is reporting an error in your .htaccess file. A strong candidate for this error is that you have a comment character (#) that is not at the start of a line. Comments MUST have a # at the start of a line, otherwise they run the risk of being interpreted as arguments for commands (for which # might be a valid argument). This has always been the case, but it seems that Apache has tightened up somewhere, or possibly changed the spec for a particular command, thus causing existing .htaccess scripts to fail.