Check the following steps:
a) Friendship requests are sent in the notification area (not in the messages), so please check if the invitation was sent but you didn't accept it.
b) Be sure that you and your friend have not blacklisted each other. In that case, remove both the blacklist entries, restart the game and send a new invitation.
Every 24 hours you will be able to send a new friendship request.
a) Friendship requests are sent in the notification area (not in the messages), so please check if the invitation was sent but you didn't accept it.
b) Be sure that you and your friend have not blacklisted each other. In that case, remove both the blacklist entries, restart the game and send a new invitation.
Every 24 hours you will be able to send a new friendship request.