If you have been facing AOL server error 400 bad request, its probably occurs at the time of installation, starting and closing of Windows, etc. If you want to fix this error, you can peep at the given list to know the best solutions

 Repair Windows registry associated with the error 400
 Use Antivirus program to prevent viruses and malware
 Remove all the junk files
 Update the drivers of your PC
 Undo all the recent changes you applied
 Install AOL messenger app again
 Repair corrupted and missing files with System File Checker
 Install all the available updates on the Windows
 Perform a clean installation of the software

If you carefully follow these steps, the issue will be resolved. You can also take help from experts by contacting AOL tech support number

Read More: - AOL customer service phone number