Question about Outlook Express

I installed Windows 10 recently. When I discovered it was not compatible with my company software and local MLS software with my Realtors Association, I used the option provided by MSN to uninstall it and go back to Windows 7 and Live Mail. Since then, my emails are deleting after about 30 days. The sender and subject line are there, but when I try to open it, the body of the message shows "cannot find message". This just started after the uninstall of Windows 10. How do I stop this from happening and, if possible, how do I recover the lost messages?

Thanks

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I tried what Firedog suggested as to going to Properties, Servers, chkng authentication Apply, OK Still did not resolve problem. Here is error msg:

Server error 530 530 Authenciation required R0107005

Error Id 0X800cc78

Protocol smtp Port 25  secure (sel) no

test msg did no go out, got window asking for PW which it did not accept. Went back to Servers and unchkd box, still no help.....

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Noel,

I could certainly use your assistance on a problem similar to Edward's

When I try to send anything it does not go out, but goes to my Outbox.

I get an error message, but I have checked my connections with Time Warner and they are correct.

The fix  did not help my problem.

This is the error message I receive:

The message could not be sent. The setting for your outgoing email [SMTP] server might need to be configured. To find the server settings for *** Email address is removed for privacy ***', please contact your email service provider.

Subject 'email message'

Server Error: 451

Server Response: 451 Outbound mail refused - 75.80.31.217 - See http://www.timewarnercable.com/en/residential-home/support/topics/internet/email-setup.html [R0209002]

Server: 'mail.twc.com'

Windows Live Mail Error ID: 0x800CCC79

Protocol: SMTP

Port: 587

Secure(SSL): No