Friends, sometimes due to some reason u can't send birthday wishes to ur friends, But here is a solution

Steps:

1. First of all log into your Facebook Account.
2. Visit the website.
3.  Now Click on CONNECT WITH FACEBOOK. 
4. Now it will run a app , Allow the application to post.

Now u will see below pic

5.  Now on right side there will be drop down box.

6. Click on Write Message.

7. Click Happy Birthday.

8. Now save it.

 Now it will automaticaly Send birth day msg to ur friend on his Birth day date.