Error 28 when sending SMS to short numbers I am using Android 6.0 and when I try to send SMS (via Hangouts or Messenger) to a 4-digit number, I get a confirmation pop-up and then an error saying


  Can't send message with SIM_NAME, error 28


I've tried to clear cache. Messages to regular numbers can be sent without any problems.

Why, and how to fix it?
There's a possibility that the short number/code hasn't been registered by the operator.

There are 2 similar cases happen with different operator:


Sky Mobile


  Why won't my phone allow me to send an SMS to a 5 digit number? It keeps telling me error 28 try again. I only activated my SIM card on Saturday.
  
  
  
  Not all, if any, short codes are supported on Sky Mobile I’m afraid

ID mobile


  I enter a few text competitions a month that use short codes, usually ITV competitions or the Gadget Show. However the new Gadget Show competition that uses short code 65555 will not send and I simply get a popup error of: Cannot send message with id - error 28
  
  Everything else works, phone, internet, texting. I even entered another competition that uses a short code beginning 6 and that works fine. I still have loads of unused credit before I reach my cap.
  
  Gadget show comp has changed the SMS number this series and I read somewhere that short codes have to be manually registered with the network providers to work, so maybe ID have not enabled 65555 yet??
  
  
  
  Hi all, we've got the problem sorted that was preventing you sending a message to 65555.



If that's the case, then there's really nothing that can be done from the user's side except by letting their operator know and request to allow/register the short numbers. Otherwise, switching to a different operator is the last alternative.