How can I fix an AOL error code 400?

AOL Error code 400 means 400 Bad Request (Invalid URL), it is an HTTP Error code

Why AOL Error Code 400 occurs?

It triggers the error when a user requests to load a website, the request will be sent to website’ server but due to an overload of multiple requests, or due to other issues the request could be rejected.

Commonly AOL Error Code 400 is displayed due to entering the wrong URL in the browser.

Other Reasons

AOL Instant Messenger is not installed properly
Windows registry corrupted
Attack of malicious program or virus.

How to Fix AOL Error Code 400

Double check the URL you are requesting, if its not proper or invalid contact AOL team.
Directly Contact AOL team for the error request
reinstall AOL Instant messenger App.
Check windows registry for AOL/Browser
Check system with an antivirus or antimalware software to verify whether there is an attack of a malware or virus.