The Infomation below was collected via FaceBook Warnings & Blocks.
Why am I blocked from sending friend requests?
If your account is temporarily blocked from sending friend requests, it may be because friend requests you’ve sent have gone unanswered or been marked as unwelcome. In the future, you should send friend requests to people you have a real-life connection to, like your friends, family, coworkers, or classmates. Make sure to use your real name and picture to help the people you're friending recognize you. If you're interested in receiving updates from people you find interesting, but don't know personally (ex: journalists, celebrities, political figures), try following them instead of sending them friend requests.
Why am I blocked from sending messages?
If you’ve been blocked from sending messages on Facebook, it may be because you sent a lot of messages recently or people reported your messages as unwelcome. Make sure to use your real name and picture to help the people you're messaging recognize you. Please also keep in mind that this block is temporary. You can still use other Facebook features to connect with your confirmed friends while you're in this block. Once your block is over, please only send messages and friend requests to people you know personally. To learn more about our policies, please review the Facebook Community Standards. Note: If you're blocked from sending messages, you may also be temporarily blocked from sending friend requests.
I'm blocked even though I’ve only sent friend 
requests to people who know me.
It's possible that your friend requests were reported as unwelcome. The people you've sent friend requests to might not recognize you on Facebook if they haven't seen you recently (ex: an old neighbor or friend from high school). Help people recognize you by using a real picture of yourself as your profile picture. You can also add an alternate name, like your nickname or maiden name, to your account. If you're worried someone might not recognize your photo or name, but they know you, send a message to them along with your friend request. You’ll be able to send friend requests again soon. In the meantime, you can still use other Facebook features to connect with your Facebook friends.
How can I make sure I don’t get blocked 
from adding friends again?
Only send friend requests to people you know in real life, like your friends, family, coworkers or classmates.
Remember that people might not recognize you on Facebook if they haven't seen you recently. Help people recognize you by using a real picture of yourself as your profile picture. You can also add an alternate name, like your nickname or maiden name, to your account.
If you’ve met someone that you’d like to connect with on Facebook but you’re not sure that person will remember you, send a message first to re-introduce yourself.
I’m trying to meet people to play games with.
Facebook is a place for connecting with people you know personally, like your friends, family, classmates and coworkers. If you’re using Facebook to play social games, you should invite your existing Facebook friends to play with you or find games that don’t require you to send friend requests to strangers in order to keep playing. If you keep sending friend requests or messages to people you don’t know, your account could be blocked from sending friend requests.
Can I still use the rest of Facebook while I'm 
blocked from sending friend requests?
Yes. During a friend request block, your account is only blocked from sending friend requests and messages to people you don’t know. This block is temporary, and you can still use other Facebook features while you're in the block.
How long will the block on my account last? Can it be lifted?
The block on your account could last between a few hours and a few days, depending on situation. Unfortunately we can't lift this block for any reason. When the block is over, please slow down or stop this behavior (ex: send fewer messages each day, only tag people in photos they're actually in, etc.). Otherwise, your account could be permanently disabled.