i checked my apache error log and find out this error
[core:alert] [pid 5220:tid 916] [client ::1:64537] C:/Users/alex/wamp/www/mysite/.htaccess: Invalid command ‘Header’, perhaps misspelled or defined by a module not included in the server configuration
here is my .htaccess file
Header unset Pragma
FileETag None
Header unset ETag
## EXPIRES CACHING ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access plus 7 days"
ExpiresByType image/jpeg "access plus 7 days"
ExpiresByType image/gif "access plus 7 days"
ExpiresByType image/png "access plus 7 days"
ExpiresByType text/css "access plus 7 days"
ExpiresByType application/pdf "access plus 7 days"
ExpiresByType text/x-javascript "access plus 7 days"
ExpiresByType application/x-shockwave-flash "access plus 7 days"
ExpiresByType image/x-icon "access plus 7 days"
ExpiresDefault "access plus 1 seconds"
</IfModule>
## EXPIRES CACHING ##
<IfModule mod_headers.c>
<FilesMatch ".(js|css|xml|gz|html)$">
Header append Vary: Accept-Encoding
</FilesMatch>
</IfModule>
<FilesMatch "\\.(js|css|html|htm|php|xml)$">
SetOutputFilter DEFLATE
</FilesMatch>
# BEGIN gzip file compression
# Compress HTML, CSS, JavaScript, Text, XML and fonts
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/vnd.ms-fontobject
AddOutputFilterByType DEFLATE application/x-font
AddOutputFilterByType DEFLATE application/x-font-opentype
AddOutputFilterByType DEFLATE application/x-font-otf
AddOutputFilterByType DEFLATE application/x-font-truetype
AddOutputFilterByType DEFLATE application/x-font-ttf
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE font/opentype
AddOutputFilterByType DEFLATE font/otf
AddOutputFilterByType DEFLATE font/ttf
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE image/x-icon
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/javascript
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
# Remove browser bugs
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
Header append Vary User-Agent
# END gzip file compression
# BEGIN W3TC Browser Cache
<IfModule mod_deflate.c>
<IfModule mod_headers.c>
Header append Vary User-Agent env=!dont-vary
</IfModule>
AddOutputFilterByType DEFLATE text/css text/x-component application/x-javascript application/javascript text/javascript text/x-js text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/json
<IfModule mod_mime.c>
# DEFLATE by extension
AddOutputFilter DEFLATE js css htm html xml
</IfModule>
</IfModule>
# END W3TC Browser Cache
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
# BEGIN WP Performance Score Booster Settings
## BEGIN Enable GZIP Compression ##
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE image/svg+xml
SetOutputFilter DEFLATE
</IfModule>
## END Enable GZIP Compression ##
## BEGIN Vary: Accept-Encoding Header ##
<IfModule mod_headers.c>
<FilesMatch "\.(js|css|xml|gz)$">
Header append Vary: Accept-Encoding
</FilesMatch>
</IfModule>
## END Vary: Accept-Encoding Header ##
## BEGIN Expires Caching (Leverage Browser Caching) ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access 2 week"
ExpiresByType image/jpeg "access 2 week"
ExpiresByType image/gif "access 2 week"
ExpiresByType image/png "access 2 week"
ExpiresByType text/css "access 2 week"
ExpiresByType application/pdf "access 2 week"
ExpiresByType text/x-javascript "access 2 week"
ExpiresByType application/x-shockwave-flash "access 2 week"
ExpiresByType image/x-icon "access 2 week"
ExpiresDefault "access 2 week"
</IfModule>
## END Expires Caching (Leverage Browser Caching) ##
# END WP Performance Score Booster Settings