Is this a corporate account and you're trying to access it from outside the corporate network?

no this is a personal account

http://atcjet.com/ appears to be configured correctly in DNS.

However the settings your posting are so old fashioned that I would question their validity. And I am dubious about the server name to be used as well.

The MX record in DNS advertises the mail server to be atcjet.com not mail.atcjet.com

What settings did the mail admin provide for configuring a mail client?

These are the settings that my isp gave me, mail.atcjet.net

There's more required than just a server name. What's needed is the server name for both, incoming and outgoing server, as well as ports and security settings for both directions. The format of the user ID is important as well, sometimes it's the entire email address, sometimes it just the part in front of the @ sign. Only your email provider can tell you the correct settings.

all my mail settings are as in my first post with the attachment of my settings. these are all my settings that my isp gave me my smpt, incoming, outgoing pop3, now I know everything is good and does work because i can setup with all the same settings in windows live mail and it will set it up so i figure it has to be something in thunderbird not my settings since they work in windows live mail

re: your first image.

POP3 incoming : mail.atcjet.net It looks like you have got a blank space before the word 'mail. in which case remove it and click on retest. Make sure there are no hidden blank spaces at the start or end of email address and server names. Test by putting cursor in the text area and use the left and right arrow keys to navigate. when you get to start or end of the letters press again to see if cursor moves another 'blank' space.

re :I have disabled my antivirus and firewall (windows defender)

You need to make sure that Thunderbird is set to Allow as completely turning this off is not advisable.

I checked and there is no space at the beginning or at the end of the server names and the outgoing and incoming. As for the antivirus I just disabled it for the moment to see if it was causing the problem. I'm not sure how to add Thunderbird to the allow list in windows defender but I am looking into it.

Located some more info: http://www.atcnet.net/support

Info says:

• incoming server name is pop.atcnet.net
• outgoing server name is mail.atcnet.net

Additional....Sorry...I have just reslised this is for atcnet not atcjet