Mail not sending

I installed eM Client about 2 months ago and thought it was working fine. I receive emails no problem but it seems all the time I thought I was replying that the emails were not in fact being sent. This has become apparent of late when I have received a couple of phone calls asking me to resend stuff. I have since tried to send emails to myself on another device and on several different addresses and the only time it has actually sent anything was when I sent something to myself on a outlook address. My main account that I have set up on eM Clent is my account. The settings that it set up automatically are Incoming:- POP3 and Outgoing :-

Hi Peter

Check the POP settings listed at for Tinyonline are what you see in eM Client account settings, you may have to manually change some of them

Hello Peter,
definitely check the setting John above mentions.
Also, if you messages are not being sent, there should be error messages in the Tools>Operations window. Please try to send one and copy the error message from there.

Also, what version of eM Client are you currently running? Check the full number in Help>About section.