I can receive but I can't send emails from iphone via imap

I can receive but I can't send emails from iphone via imap

Good morning! I sent off 2 emails this weekend from my iphone and I didn't realize that they were sitting in my outbox. I received a message that said "cannot send mail, an error occurred while delivering this message."

I followed the instructions on the website regarding setting up zoho mail on my iphone, so I'm not sure what happened.  Can someone please help? Thanks! :)