Why can't i send MMS

So I have never had this problem before but starting about 3 days ago My samsung galaxy s7 from Sprint will not let me send MMS. I haven't changed anything on my phone that I can remember. I did change my number and it seems that it started after that. That was on Friday morning and I havent been able to send MMS since. So not sure whats happening there. I need help, anyone please! lol

from Android Forums at AndroidCentral.com - Ask a Question http://ift.tt/2eqH8WP
via IFTTT