The usual use of the 403 message is if you try to open something that requires a membership or login. The message can be returned from the place you're trying to get into, or from your own computer based on some error code from the site or from a list of messages in the innards of your browser.

The most common cause of an unexpected error is probably mistyping the site address. It's a little more mysterious if you use a link in your Favorites/Shortcuts, since usually what works one time works every time.

Even with a reliable link, the error may still appear due to a failure/error by your internet provider (ISP) or of any of the inevitable relay servers that passes stuff across the web.

The URL (universal resource locator) that you type (mudcat.org) isn't really the "address" of the site, but has to be "translated" to the numerical "IP" value actually used by the web. The translation is done most generally by certain of the relay servers, and occasionally one of them gets it wrong. When one of the relays gets a request it doesn't recognize, it "asks" another server for the right translation, and if the first server doesn't get an answer it passes the message to another server until one of them finds the right answer. If a server has been down and has lost it's "answers" the search to restore it's stock of translations can sometimes take a relatively long time, and could possibly result in a failure to connect. (Rebuilding of the translator/address lists is occasionally due to a "redirect" malware attack on the server, in which case it may be simplest for the server to "delete and rebuild." It's hard to say how often this may happen, but we all hope it's rare.)

Fairly rarely, a new "update" may fail to install correctly on your computer, especially if the computer isn't always on to receive the updates, and isn't on long enough to get everything installed when it's been down for a while. This may "spontaneously" be corrected the next time you're turned on for a while, depending on how you've set up to receive and install patches. This can come from OS updates, browser updates, or Malware Protection program updates.

Browser settings may block certain sites, but I haven't heard of any that would give a "403" error. Mine tells me my toes will rot, I'll go blind, and the apocolypse will begin if I connect to a site, but then politely asks "are you sure you want to." If you let us know what OS (Windows/Mac/Unix) and browser (IE/Chrome etc) you use, and possibly what kind of AV/popup blocker/site safety you have turned on, someone might know of a "quirk" peculiar to your setup; but advice is still likely to be pretty generic.

Surprisingly, "dirty sites" are, as a rule, probably safer than lots of other places, since they're making (lots of) money off the connection and are very seriously conscientuous about keeping malware out (with some exceptions, of course). It's probably not a real test of your system to go there, but we won't tell anybody if you just need an excuse - suit yourself.

If the problem doesn't happen again, there's probably little reason to worry a lot about what actually caused it. "Temporary Glitch" is about as good an explanation as we're likely to find without enough information to let someone else get the same message the same way you did.

John