-- One program gave me an error as "Connection Closed Gra...

[mdk]

@ajhilker -- One program gave me an error as "Connection Closed Gracefully". That means Shaw Mail Server blocked email downloads.

Your conclusion in your second sentence does not follow from your observation in your first sentence.

Most mail-servers will "time-out" after some length of "inactive" time, causing your E-mail client to report a "graceful" end of the connection.

It is not likely to be a matter of "blocked" downloads, unless your computer's anti-virus software has scanned a download, and has blocked your computer from accessing it. 

Also, some E-mail clients can be configured to NOT automatically download attachments, in an attempt to protect your computer from malicious attachments.

[ajhilker]

Well, to follow up. As of yesterday, I deleted numerous emails with Windows 10 Mail (the only email reader that would work on my computer) and I did a Restart your Gateway. SeaMonkey started downloading emails again! At first slowly and it seemed from that last deleted email. As I deleted more emails, it then downloaded all the latest emails at it's usual rapid speed. It seems to be working as usual now. So my guess is that there was a problem with Shaw Webmail, possibly some kind of defective email or some thing like that. Don't know why Shaw wouldn't know about that.

[mdk]

@ajhilker -- As I deleted more emails, it then downloaded all the latest emails

How full is your "C:" drive?  Maybe, deleting some messages created free-space for more messages to be received & stored?

If you "empty" your E-mail program's "Trash" folder, does that help?

Windows has a "Disk Cleanup" app, to identify and remove files that are no longer required. Have you run that app?

[dssnidal]

Mine is exactly the same problem and it’s happened twice.