Can't send e-mail

I can’t send an e-mail. I did a diagnosis and it showed OK, and actually sent a confirming e-mail. But, when I try to send a regular e-mail to myself, it doesn’t work. I tried sending to my wife’s e-mail, and that doesn’t work either. I can receive. I checked with my internet provider, and all the server settings are correct. I also tried sending an e-mail from my smart phone, and that worked also, so it’s not a provider problem - it’s a problem with eM Client. What can I do???

This is a follow-up to my previous question. My default e-mail is with cox (a cox.net address), but I also have a gmail account. I can send from my cox address to my gmail address, and can send from my gmail account to my cox account. But, I cannot send from my cox account to either my own cox address or my wife’s cox address. I checked with Cox again to see if something was blocked, but they said all the settings were OK. While on the Cox web site, I can send from my cox address to my cox address, but cannot do so with eM Client. HELP!!

Hello,

can I ask you for screenshot of your Tools - Accounts - gmail account - SMTP tab?

Jan