Invalid number error message when sending text from my iPhone
Ever since I upgraded to an iPhone 5s I get an Error Invalid Number message when sending a text to a phone number that used to work just fine from my 4s. In fact I can receive a text from this number but when I try to reply to that text I get the error message again.
I deleted the contact info in case there was something broken there and I'm trying it with just the raw phone number but without any luck. What can I do? It's my boss's number so it's important I fix this problem.
All other contacts and texts are working just fine, it's just this one phone, a Samsung galaxy on T-mobile if that helps.