I would have to say it sounds like an issue between you carrier and the destination carrier. You would have to call your carrier's customer service to inquire and possibly resolve the issue.
I live six months in France and six months in India, and can't seem to be able to send text meaages from one country to the other. I can do so towards most countries, including the USA, the UK, Sweden, Malaysia, Japan, etc, but not between France and India either way! This happens with whatever brand of phone I'm using. I have asked so many people, including the store people who sold me my phones, but have not got an adequate explanation so far. Could you please, please help?