Unable to add Friend in Facebook?

[soumen]

There are many consequence may happen in this regard,

>The profile (your friend) where you try to send friend request or msg it can be possible that profile owner has been disable the option i;e,request sent by unknown persons are disable I mean unknown person cannot sent any message or friend request to him
>Or the person you try to connect in Facebook that person block you from doing that (the chances are doing so are very low,whatever may be the reason),

From my own experience,you can connect with him/her,you go to friend list of him/ her,try to detect any common friend you know and then connect via that friend.There is also one problem may arise,The person yoy trying to connect he may be also disable the option of seeing FRIEND LIST by any person.So in that case you are helpless my friend.