Can't get mac line back online - a continual problem

Question

Hello,
I've read most all the posts I can find on this subject.  Mac air mac mail goes offline and I just can't get it back on.  I've changed nothing with MY mail, but all of a sudden it just goes offline, then I cannot get it back online.
I have tried "network diagnostics" via going to System Preferences > Network > and my computer is on line.
If I go to the Mail Connection Doctor, the top line says: Mail was able to connect to the Internet; however, all my accounts have red dots, not green ones, AND the actual "network diagnostics" option is grayed out.
On every email account I have it says: Could not connect to this SMTP server.  Check your network connection and that you entered the correct information in the Account preferences (nothing has changed so all information is correct). Also verify that the server supports SSL.  If it does not, deselect the "Use SSL" checkbox in the Advanced tab of Account preferences.  I have tried it both ways, checked and unchecked. My server supports SSL, and it was always set with that checked.
I was getting and sending mail a couple days ago.  Nothing has changed except Mac mail and not being able to get it back online.  And this happens all the time.  It gets so old.
I also went to Mailbox > Take all accounts ON LINE > but nothing happens when I click on that.  I cannot click on take it OFF LINE because it's grayed out.  I thought I'd toggle back and forth and see if it helps.
So everything is just grayed out, yet I am connected to the internet and conneted to my WIFI and nothing has changed from a couple days ago, EXCEPT my mail is now OFFLINE and I can't send or receive.  Well, the "mail is offline" is grayed out, and "take all mail online" is not. All the accounts have the little triangle icons next to them.  If I click on those it says Connection Failed: 5 accounts have connection failures. Click the indicator next to each account for details.  Then I get two options "stay offline or take all accounts online. 
So many conflicting messages -- it's online, take it off, it's off line, take it on, unable to connect to internet (except I'm here connected to the internet), network diagnostics grayed out, yet status tab in the bar across the top says "OFFLINE" and there is no way to put it back online.
Really crazy! This happens all the time -- all the time.  And then I post and browse and google and nothing gets accomplished and I forget about it and use other computers and devices to send email.  Then one day it'll just start working again.
How can I fix this once and for all and stop this nonsense of having it goo offline and not being able to get it back on using ALL the options available?
I need to add: I have deleted the account and re-added the account, but I always get the mail message:
The MobileMe IMAP server “mail.me.com” is not responding. Try checking the network connection, and that the server name is correct. Otherwise, the server might be temporarily unavailable. If you continue, you might not be able to receive messages.
Mobile Me is non existent now, but that is what MY computer message tells me.  And again, my network connection is fine, just not for EMAIL.
Thanks for any help.
Message was edited by: Pamela Kinann

Answer 1

Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, or by a peripheral device. 
Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode* and log in to the account with the problem. The instructions provided by Apple are as follows:
Shut down your computer, wait 30 seconds, and then hold down the shift key while pressing the power button.
When you see the gray Apple logo, release the shift key.
If you are prompted to log in, type your password, and then hold down the shift key again as you click  Log in.
*Note: If FileVault is enabled under OS X 10.7 or later, or if a firmware password is set, or if the boot volume is a software RAID, you can’t boot in safe mode. Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs. The next normal boot may also be somewhat slow.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin. Test while in safe mode. Same problem? After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.