Cannot get or send mail using Apple Mail on iPhone and iPad

Question

Everyone in my household cannot get or send mail on their Apple Mail for iPad and iPhone. We all get the same message: "The user name or password for [account] is incorrect." This just started happening yesterday afternoon. No problems before that. I called my hosting company and Apple, and both blamed the other. My Apple system is always updated, so I have the latest version of Maverick. Had no problems with it up until now.
However, I awoke this morning to find downloaded emails in the same program, but when I go to "get mail," it says the same thing, and still won't allow me to send or receive.
Here's the kicker. I also use Gmail with the exact same accounts (yes, I need both since Apple Mail does things that Gmail doesn't, and vice versa). No problem! I get all my emails and can send with no problem. So, my hosting company claims it can't be them (makes sense). It only happens using Apple Mail, and I have several email addresses. None of them work (other than the strange phenomena of suddenly getting some of them downloaded for no apparent reason).
What do I do from here? I've changed passwords, deleted and tried to set up my emails, only to get the message that they probably will not work. And they don't. I have shut down and restarted my iPad and iPhone, to no avail.
Thank god for my Gmail account, or my business would be closed.
Again, this is happening on four devices in my home: 2 iPads and 2 iPhones.

Answer 1

I have a comcast account I use on my phone and use it for receiving and sending mail. When you look at the account in settings, you need to check each of these
incoming mail server: mail.comcast.net
username: the part of your email address before the @
password: your password
outgoing mail server: smtp.comcast.net
Under Advanced
Use SSL: On
Authentication: Password
Server Port: 995
If you cannot make it work from changing settings in the account, delete the account and start over. Use the "Other" setting when starting the account. It is a POP3 account and make the entries I gave you. Once you do that, it should check the entries and validate the account. You shouldn't have any trouble from there. Those settings will work from either the iPhone on cell, or wireless. Mine will even work when I'm at home on my wireless there, which is on the Comcast network.
Hope that helps you.