The message of "Page not found" on the homepage

[SWSUSA]

Originally Posted by Dave

So even when you upload the original forum.php and index.php file, the same problem is happening?

Yes. Да.

Originally Posted by Dave

Definitely a bad plugin/hook or .htaccess file.

I assume that it because of settings of the web server or because of one of the established spendthrifts.

Я предполагаю, что это из-за настроек веб-сервера или из-за одного из установленных модов.

--------------- Added [DATE]1449667976[/DATE] at [TIME]1449667976[/TIME] ---------------

I solved a problem. It because of a code in the .htaccess file.
With such code the site ceased to open:

Решил проблему. Это из-за кода в файле .htaccess.
С таким кодом сайт перестал открываться:

# Block User-agent Libwww-perl
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} libwww-perl.* 
RewriteRule .* – [F,L]

<IfModule mod_rewrite.c>
	RewriteEngine On

	# If you are having problems or are using VirtualDocumentRoot, uncomment this line and set it to your vBulletin directory.
	# RewriteBase /

	# If you are having problems with the rewrite from content/ to content.php, uncomment this line to turn MultiViews off.
	# Options -MultiViews

	RewriteCond %{REQUEST_URI} !(admincp/|dbseocp/|modcp/|cron|mobiquo|forumrunner|api\.php|reviewpost/|classifieds/|photopost/)
	RewriteRule ^((archive/)?(.*\.php(/.*)?))$ dbseo.php [L,QSA]

	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteCond %{REQUEST_FILENAME} !/(admincp|dbseocp|modcp|clientscript|cpstyles|images|reviewpost|classifieds|photopost)/
	RewriteRule ^(.+)$ dbseo.php [L,QSA]
</IfModule>

# proc/self/environ? no way!
RewriteCond %{QUERY_STRING} proc/self/environ [OR]
# Block out any script trying to set a mosConfig value through the URL
RewriteCond %{QUERY_STRING} mosConfig_[a-zA-Z_]{1,21}(=|%3D) [OR]
# Block out any script trying to base64_encode crap to send via URL
RewriteCond %{QUERY_STRING} base64_encode.*(.*) [OR]
# Block out any script that includes a <script> tag in URL
RewriteCond %{QUERY_STRING} (<|%3C).*script.*(>|%3E) [NC,OR]
# Block out any script trying to set a PHP GLOBALS variable via URL
RewriteCond %{QUERY_STRING} GLOBALS(=|[|%[0-9A-Z]{0,2}) [OR]
# Block out any script trying to modify a _REQUEST variable via URL
RewriteCond %{QUERY_STRING} _REQUEST(=|[|%[0-9A-Z]{0,2})

With such code the site opens:
С таким кодом сайт открывается:

# Block User-agent Libwww-perl
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} libwww-perl.* 
RewriteRule .* – [F,L]

# proc/self/environ? no way!
RewriteCond %{QUERY_STRING} proc/self/environ [OR]
# Block out any script trying to set a mosConfig value through the URL
RewriteCond %{QUERY_STRING} mosConfig_[a-zA-Z_]{1,21}(=|%3D) [OR]
# Block out any script trying to base64_encode crap to send via URL
RewriteCond %{QUERY_STRING} base64_encode.*(.*) [OR]
# Block out any script that includes a <script> tag in URL
RewriteCond %{QUERY_STRING} (<|%3C).*script.*(>|%3E) [NC,OR]
# Block out any script trying to set a PHP GLOBALS variable via URL
RewriteCond %{QUERY_STRING} GLOBALS(=|[|%[0-9A-Z]{0,2}) [OR]
# Block out any script trying to modify a _REQUEST variable via URL
RewriteCond %{QUERY_STRING} _REQUEST(=|[|%[0-9A-Z]{0,2})

<IfModule mod_rewrite.c>
	RewriteEngine On

	# If you are having problems or are using VirtualDocumentRoot, uncomment this line and set it to your vBulletin directory.
	# RewriteBase /

	# If you are having problems with the rewrite from content/ to content.php, uncomment this line to turn MultiViews off.
	# Options -MultiViews

	RewriteCond %{REQUEST_URI} !(admincp/|dbseocp/|modcp/|cron|mobiquo|forumrunner|api\.php|reviewpost/|classifieds/|photopost/)
	RewriteRule ^((archive/)?(.*\.php(/.*)?))$ dbseo.php [L,QSA]

	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteCond %{REQUEST_FILENAME} !/(admincp|dbseocp|modcp|clientscript|cpstyles|images|reviewpost|classifieds|photopost)/
	RewriteRule ^(.+)$ dbseo.php [L,QSA]
</IfModule>

The part of this code is necessary for fashion [DBTech] of DragonByte SEO v2 (vB4). Though itself fashions at me it is switched off.
Часть этого кода нужна для мода [DBTech] DragonByte SEO v2 (vB4). Хотя сам мод у меня выключен.

The part of this code optimizes a forum, increasing the speed of loading of pages.
Часть этого кода оптимизирует форум, увеличивая скорость загрузки страниц.