How to use my mail app in my iphone on a school internet?

Why when I use my mail app in my iPhone, I can receive emails but I can't send one and I'm connected to the internet in our school. When I try to send an email on a computer using the same internet it works fine… When I use in my iphone it just says "sending" for a long time then goes to the outbox… How can I fix this?

Try using an alternate mail app. I do not have an iPhone, so I don't know much about that topic, but I'm sure your school has some sort of block/filter which only allows their computers to work on it, but not sure how your phone still receives the mail?
~Nate