Very glitchy.

I am also having issues as well. Some of the forum threads are not loading.

I tried clicking into the Milebuzz thread, but hyperlink shows as: "http://www.flyertalk.com/forum/milesbuzz-370/.%20$uredir%20." which already seems a bit odd.

The error message I get is: "Page not found"

From where?

From the FT forum home page, I see the proper URL for that forum:

http://www.flyertalk.com/forum/milesbuzz-370/

No troubles from here, and I've been on and off all day.

I have not been able to click onto MyFlyerTalk from my laptop all day. Same issue: "Page Not Found." Before that, I get a page full of junk for a second or two.

Yup, same for me all day. The usercp.php page is just a bunch of jumbled text, then it redirects to a page not found.

The same was happening for me last night and this morning: when I am trying to get to usercp.php page, it flashes some scrambled text (possibly php code), and then redirects to http://www.flyertalk.com/forum/.%20$uredir%20.
with "Page not found".
Attempts of going to /forum/ result in the same.
But I can get to http://www.flyertalk.com/
This happens in one browser (Slimjet in this case, but I don't think it matters), and only when I am logged in. If I go to http://www.flyertalk.com/forum/ in the "incognito" window, it works.
In a different browser (FF, Opera), it works even when I am logged in.

So, I assume it has something to do with cookies that the server started setting yesterday (or a day before yesterday). And those must be cookies responsible for the persistent login in FT.

So, I tried to delete all cookies that pertain to *flyertalk.com.
Apparently, that is not sufficient. It still doesn't work. But I see that the website still thinks I am logged in. So, there might be a cookie that is in a different domain. What is it?

Which cookie(s) is(are) responsible for the persistent login in flyertalk
besides those with flyertalk.com?
I'd like to delete it (them) to effectively "logout" and fix this in the browser I am using.

So when I click that link that you provided, it re-directs me to this page:

http://www.flyertalk.com/forum/milesbuzz-370/.%20$uredir%20.

(including the period at the end of the hyperlink)

On that page, I see the message: "Page not found"

However I just cleared my cookies and it works fine now.

Yes, clearing all cookies should do the trick.
Personally, I just don't like deleting all of them, as that resets states for many other sites.

In my cookies, I see that there are some cookies listed for "flyertalk.com" and some listed for "www.flyertalk.com" (8 cookies and 9 cookies, respectively). Did you delete both?

Yep. See that wild-card asterisk?

Yup. Cleared all cookies, and everything seems to be working fine now.

Many thanks, site gods!

I did see it, just making sure.

Working again for me too, and I didn't clear anything.

An update/correction:
I was wrong: Deleting all cookies for *flyertalk.com did delete persistent login. But it didn't clear the problems getting to the page linked from the big "My Flyertalk" button at the top right: http://www.flyertalk.com/forum/usercp.php
That page and http://www.flyertalk.com/forum/ still do not work for me in this browser. But they work in the incognito window of the browser.
So, I suspect some 3rd-party cookie might be the culprit.