Yhe usual cause is anti virus/ Security suite blocking Thunderbird connections to the internet, either through a firewall, or a poorly implemented mail scanner that knows nothing of setting up accounts.So verifiish as it treats the process as getting mail.

restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

WHBile in safe mode try setting up your account. This mode will disable some security software and often works, otherwise, check the firewall, and turn off any email scanning.

While switching over to safe mode I had attempted to add my account into ThunderBird. The results were the same. More info in the image

I am confused you apparently have four account working. so another should work. Did you enable pop n the Outlook.om web site?

It seems like that's not the problem. I'm trying to connect with IMAP and tried with POP aswell

Is the password longer than 16 characters, the limit for outlook accounts?

No, I'm able to log into Windows Live Mail and outlook.com just fine with the password I have

The limit on password length applies to POP and IMAP mail clients. AS WLM uses webdav as an HTTP protocol for connections to hotmail and the web site uses plain HTTP there is no comparison. A bit like saying you can get to Chicago. by plane when the road is closed by flooding. The result might be the same, but the process of getting there proves nothing

Given the number of account you have, what is the frequency they are checked? Could it be your logged into hotmail when your trying to create a new account and it is not working?

Is the account setup on a phone or other device? Try turning that device off.

If you have Push enable on a device for mail, try turning that off.

I have all these accounts already created. They all work and have all been getting mail and sending mail. I've had them all on Windows Live Mail application fully functional. The only major trouble is this one account.

I don't have any of the mail going to any mobile devices.

The newest account I have is from about 3 years ago for lilrock@outlook.com. My oldest account is quite old (darkstone_rocks@hotmail.com) and I can't remember when I got it.

Windows Live Mail is accessing the account by "https://mail.services.live.com/DeltaSync_v2.0.0/sync.aspx". I can't just put that into ThunderBird. The auto detect system works and is identical to the other Microsoft email accounts.

I contacted Microsoft support for further assistance since I believe the trouble is on their side or with the account itself. When I receive a result I will post the answer here.

Another reason for the setup failure would be if this account has two-step verification.

http://windows.microsoft.com/en-ca/windows/app-passwords-two-step-verification

I must tell you how to solve the connection problem