Apache errors

Have slow GUI issue and checking the logs.
Found in /var/log/apache2/error.log:

Fri Sep 09 00:07:48.603377 2016] [authz_core:error] [pid 1170] [client 192.168.5.61:59113] AH01630: client denied by server configuration: /var/www/html/admin/index.html
[Fri Sep 09 00:07:48.603743 2016] [authz_core:error] [pid 1170] [client 192.168.5.61:59113] AH01630: client denied by server configuration: /var/www/html/admin/index.cgi
[Fri Sep 09 00:07:48.603914 2016] [authz_core:error] [pid 1170] [client 192.168.5.61:59113] AH01630: client denied by server configuration: /var/www/html/admin/index.pl

In fact I do not have all those files on my system:

~# ll /var/www/html/admin/index.*
-rw-rw-r-- 1 asterisk asterisk 185 Sep 8 08:55 /var/www/html/admin/index.php

Any suggestion?

You are being scanned for files. This is not slowing your system down and you are not missing any files.

Thank you, Andrew, I will keep monitoring my system. For some reasons sometimes it’s very slow when I’m accessing GUI, progress bar stops at 68%, then System Overview is collapsed. Only sometimes, cannot see the logic yet.