If you are using Gmail it is because gmail does not deliver it, their view is you have a copy in your sent folder. You do not need two of them.

You can always send an email as "new" right click any email and select edit as new message from the menu..

Thanks, Matt. I do not use gmail. I have Comcast. Bloody thing is still acting up. I have always been able to copy and paste a quote or photo and e-mail it to my own e-mail address with no problem. This started abruptly several days ago. It shows in the "Sent" folder...but is not received as new e-mail. I thought perhaps it may have something to do with a T-Bird update. I always update when notified. Thanks again!

check your xfinity settings to see if you have a filter or rule that blocks you mail. https://www.xfinity.com/support/articles/spam-filters-and-email-blocking-new-experience

Apparently it is very easy to use that feature to mess things up with overly aggressive settings. (I am not a customer, so what I know is anecdotal)