RokJok,
It could be, the ISP, and it always easier to see if they fix it. If you call for support, it can be helpful if they check your settings, but when they start advocating changes, it can be a problem. It is not good news when you find the ISP had a problem, it has been fixed for hours/days, but now you still have a problem--because of changes.
It was obviously not the case here, but it is always a good idea to check your cables/plugs. The exact facts have faded but, Once their was a bad storm, ISP had a problem, and I had unplugged the DSL/Modem line. After this my system did not work. The ISP was back up. The DSL modem was now plugged in. (I had not replugged it.) I looked closer, the plug now went from the DSL modem or modem (?) back to the regular modem. With no external connection, no wonder it didn't work.

The morass of cords, probably confused someone. Plugged it in correctly and it worked fine.
Always check the simple things first!!!
Here is a humorous story (not to those who footed the bill.

)
A computer consutant came to a friends firm to replace a constantly malfunctioning hard drive. The consultant grabs the computer case and pulls it out to start work on the replacement. Guess what he found! The side of the computer was covered with those refrigerator magnets. ...probably with all the telephone numbers of the computer user's favorite luncheon spots.
Jerry,
If you need to test your email, feel free to send me a couple. I checked, my email address is in my profile, although I imagine you have it anyway, having sent me one recently. I'll respond that I got it. Further, you can usually set your message to send a receipt, although the recipient has to click, yes, it is OK to send receipt. In Outlook, it is under View, Options.
Donald