This webpage has a redirect loop accecing wordpress admin

Hi
I cant accec to wp admin dashboard, the error is:
This webpage has a redirect loop.
i did the steps below but doesnt work.
1-Disabling all my plugins does not enable me to login.
2-deleting and replacing .htaccess file doesnt work.
3-updating wordpress core files doenst work.
4- clearing browser cookies and cash.
5-trying diffrent browser.
6-trying deffrent PC to connect.

my .htaccess file content:

# BEGIN iThemes Security - Do not modify or remove this line
# iThemes Security Config Details: 2
	# Protect System Files - Security > Settings > System Tweaks > System Files
	<files .htaccess>
		<IfModule mod_litespeed.c>
			Order allow,deny
			Deny from all
		</IfModule>
	</files>
	<files readme.html>
		<IfModule mod_litespeed.c>
			Order allow,deny
			Deny from all
		</IfModule>
	</files>
	<files readme.txt>
		<IfModule mod_litespeed.c>
			Order allow,deny
			Deny from all
		</IfModule>
	</files>
	<files install.php>
		<IfModule mod_litespeed.c>
			Order allow,deny
			Deny from all
		</IfModule>
	</files>
	<files wp-config.php>
		<IfModule mod_litespeed.c>
			Order allow,deny
			Deny from all
		</IfModule>
	</files>

	# Disable Directory Browsing - Security > Settings > System Tweaks > Directory Browsing
	Options -Indexes

	<IfModule mod_rewrite.c>
		RewriteEngine On

		# Protect System Files - Security > Settings > System Tweaks > System Files
		RewriteRule ^wp-admin/includes/ - [F]
		RewriteRule !^wp-includes/ - [S=3]
		RewriteCond %{SCRIPT_FILENAME} !^(.*)wp-includes/ms-files.php
		RewriteRule ^wp-includes/[^/]+\.php$ - [F]
		RewriteRule ^wp-includes/js/tinymce/langs/.+\.php - [F]
		RewriteRule ^wp-includes/theme-compat/ - [F]

		# Disable PHP in Uploads - Security > Settings > System Tweaks > Uploads
		RewriteRule ^wp\-content/uploads/.*\.(?:php[1-6]?|pht|phtml?)$ - [NC,F]
	</IfModule>
# END iThemes Security - Do not modify or remove this line

# 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

my site: http://www.tfiranian.com/wp-admin

how can fix this ?