I can receive emails, but cannot send any.

Are you receiving any error messages? If so, posting the complete error message, plus a screenshot of your incoming server settings pane, may prove helpful. thank you

I am receiving an error message, but I don't know how to copy it to you. I snipped it, but it won't copy to here. I am able to send messages using Outlook.

There is a free little sniptool at https://sourceforge.net/projects/sniptool/ Just download, unzip, and start it. Very helpful when posting questions here to have screenshots. Thank you