How to get rid of error 400?

Question

Apache HTTP Server

Address bar, paros, non-existent directory
/%%%
Failed to load resource: the server responded with a status of 400 (Bad Request)
Bad Request
Your browser sent a request that this server could not understand.
Additionally, a 403 Forbidden error was encountered while trying to use an ErrorDocument to handle the request.
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How to get rid of the 400 error? Your Apache/2.4.7 (Win32) server kicks like that, there are no manuals...
PS / I note that this is a system error, here is an example
geektimes.ru/%%% it turns out, send to another category and so on.