OK, what's up with this? I changed no settings, but suddenly, I can't get jlarue.com email from my iPad 2. I continue to receive it from all other devices, using the same settings. When I go to the Earthlink live chat line, I can't get in because of unnamed outages. Since I continue to get email on my Windows work machine, my Linux home machine, and my Android phone, the problem isn't the servers, right? It has to be the iPad. I even did another software update (hadn't caught that in settings), which locked up my machine altogether until I forced it to shut down (hold down power and menu buttons for 10 seconds).
The lesson: one does get dependent on one's devices.
P.S. I finally got an Earthlink live chat to straighten it out. In brief, the latest Apple updates have stricter security policies, requiring a slight change to login settings, including a port change. They sorted it in seconds.