The request contains bad syntax or cannot be fulfilled.The relevant clue here may be that "4nn" errors are "Client Request" errors.
If you Google for information, you'll get dozens of supposed explanations. Here, a sample:
- About.com: 400 Bad Request Error Resolution
- ASP FAQ: Why do I get HTTP/1.1 400 Bad Request errors?
- CheckUpDown: HTTP Error 400 - Bad request
The problem with the Error 400 is that it is seen in very low volume - maybe 1 or 2 reports / week. It's consistent in volume - we simply don't see an affinity.
If you're seeing this, first try one of the most universally prescribed nostrums in Blogger land - clear cache, cookies, and active logins, and restart the browser. An alternative would be to try using a different browser - if this helps, you could rule out your computer in general, your Internet service, and Blogger in general being the primary cause of the problem.
Next, help us to help you and others - and answer as much as possible. Partial answers are better than no answers.
- What are you doing - are you using Blogger (maintaining your blog), BlogSpot (viewing a blog), or a non BlogSpot URL (also viewing a blog, but one published externally)?
- Are you logged in to Blogger when you see the error? If so, are you logged in using a GMail based Google account, or a non GMail based account?
- What browser and operating system (name and version please) are you using? Do you have any download accelerator, download manager, or speed enhancement add-on installed?
- What anti-malware / anti-virus / personal firewall product do you use?
- Where are you located (city, county / region / state, and country are useful here)?
- What ISP do you use? Does your ISP offer any bandwidth enhancement, download accelerator, or speed increasing option?
- How often do you see this error? How often do you not see this error? When did you start seeing this error?
- If the problem goes away mysteriously, you could tell us that, later, too.
- Seeing a report "I am having this problem." is good.
- Seeing two reports - "I am having this problem.", later followed by "I am now not having this problem.", is better.
- Seeing two reports - "I am having this problem.", later followed by "I am now not having this problem - and this is what I know changed recently:", is better still.
(Update 2011/06/30): Today, we are seeing a significant increase in Error 400 and related symptoms, reported from some portion of the Blogger community.