Finally my problem solved after trying lots of way. My domain is http://rasha.org. I was trying to signup as http://rasha.org/wp-signup.php but the signup page was not found. Finally I just go to the network interface and navigate to Sites>All Sites>rasha.org(in your case it will be your domain name)>Info> check “Muture” attribute and save. After doing this it worked like magic.
oh Canha thanks for your help. Actually I am a fool. I thought the link will work properly as I write typically in HTML. Now it works greatly.
