i cant send SMS without writing something in the subject field

whenever i want to send a SMS i need to fill both subject field and text message field becaue if I don't it won't send it,i Dont really care when it come to sending text message to iphone but when im sending a SMS to phones who support Android they can't see the text message, just the subject field.

can you give some tips on how i can solve this "can't send a SMS without a subject" thing?