Why can't I use my mobile phone to log in to 189 and send a short message?

If the account of 189 is registered in the mobile phone, send a short message, and there is no restriction on going out of the network (free email address: 100 (80 in the network, 20 out of the network, 20 per day; Open the month 100 SMS full gift); The 189 mailbox registered with broadband account or fixed telephone number only sends 80 short messages to the network and cannot be sent to other operators. If the sending is unsuccessful, please verify the registered account type of 189 mailbox. Click "official website" Customer Service 22 1 below for more service offers.