I'm having this same problem of not being able to receive email via Outlook.  I've spent considerable time with my ISP and it appears the configurations are correct.  I've reviewed the threads and have followed these steps but I'm still getting the 5.7.1 authentication error.  My ISP indicates that the 2011 version is not supported by them so I'm stuck.  How can I resolve this problem. 

The incoming server works fine but the outgoing server does not.  I've followed my ISP's instructions including overriding the default port and manually including the specified number.  I've triple checked my entries more than I care to admit.

Would appeciate any guidance.

Thanks much.  John
I receive the following error report when using Windows Live Mail:
Server Error 250
Error ID 0x800CCC 7D
Protocol SMTP
Port 25
 
<Windows 7>
my outlook is linked to my hotmail account. whenever i try and sync..it just says "authentication failed as outlook does not support any of the available authentication methods"..have tried overriding default port..not helping..HELP!!!

My hotmail is working fine. When i log on it directly, i can send and receive mails without a problem.
I frequently get "Mail Could Not Be Received At this Time" Dialogs, more or less as described here.

This happens with multiple accounts of various types, most commonly gmail accounts. I have run keychain first aid with no issues. I tried changing the SMTP port for several accounts from 465 to 587 as recommended here, without much change. 

But the main question I have is not how to fix it permanently but how to suppress the dialog.

Is there any way to suppress this error dialog entirely? This happens to me frequently and the most annoying thing is not that Outlook cannot connect (which it does eventually), but that it puts up this error dialog.  It makes running Outlook, using automated reply filters, while unattended, impossible. It would be much better if no dialog were presented and the errors went where other errors go into that little error box.

The dock bouncing on errors is an added irritation, so much so that I already disabled it system-wide due to Outlook. There appears to be no way to turn that off within Outlook.