Fix Error 400 Bad Request http in Wordpress
Are you trying to update or publish a post/page and you get sent to that horrible page that says: 400 Bad Request Error
Maybe while trying to update you noticed that Wordpress is "saving draft" for what seems like forever and you can't even update. Well then this may fix it.
By the way, I have read others say to deactivate your plugins to find the culprit or upgrade your Wordpress version. Or try a different browser or update your browser, etc. Well, what if you have done all this and still nothing.
Wait! Before you waste hours like I did doing all that - first try this. It worked for me.
So it turns out that it may not even be your browser that is causing this either.
The simple solution is, all you need to do is Flush Your Local DNS Cache
1. Click on Start, followed by All Programs, and then Accessories.
2. Right-click on Command Prompt and choose Run as Administrator.
3. In the Command Prompt window type in the following command and press Enter:
4. If all goes well, which it should, you will see the following confirmation message:
Successfully flushed the DNS Resolver Cache.
Issue the following command for OS X Mountain Lion or Lion:
killall -HUP mDNSResponder
...for older systems try this:
dscacheutil -flushcache -or- lookupd -flushcache
Then you're going to want to log-out and back in to Wordpress. And hopefully, magically all your troubles will be over!
I hope this solves it. Good luck.