I can receive email, but I can not send it...

I can receive email, but I can not send it...

Hello! 

I just set up Zoho, and I have used this before, but I ran into a problem that I have never had before. 

I can receive email on my account, but am unable to send it. 

I have attempted to send out 4 emails to a few different addresses, and none of them have delivered. 

I saw in another post that sometimes email is deferred... is that what has happened?

Thanks, 
Matt