email problem

I've often sent emails to myself to transfer, say, a photo from one computer to another. Suddenly I'm unable to do so. The outgoing message shows in my "Sent" folder, but I don't receive it. Nothing appears in the Inbox.

I'm not aware of changing a setting anywhere, but may have done so by accident.

As an old geezer (89) I'll appreciate any help from younger, more supple minds can offer.

TIA.