I am unable to send messages from my windows live mail  and keep getting this message:

An unknown error has occurred.

Server: 'mail.optusnet.com.au'
Windows Live Mail Error ID: 0x80070057
Protocol: SMTP
Port: 25
Secure(SSL): No

One of my messages had photos attached and I opened the Windows Live ID and tried to send the messages, but the error still remained. I tried  switching the Protocol SMTP Port from 25 to 587, but still the same.

Does anyone have wisdom to share?

Regards

John Cosstick
I cannot open outlook for mac 2011 anymore
the error message reads "Could not change to that identity. An unknown error has occurred in Outlook." I have tried to reinstall office, and have followed other advice online to identity problem.  previous to this outlook routinely wiped out my contact list, and regularly crashed.  
Attempted to send photo email which caused an error.  The error message said to delete the photo and re-send.  How do I delete the photo/message?  It is blocking the ability to send any outbound emails until I can resolve the issue.

An unknown error has occurred.

Subject ''
Server Error: 554
Server Response: 554 omta01.westchester.pa.mail.comcast.net comcast Port 25 not allowed - http://customer.comcast.com/help-and-support/internet/email-client-programs-with-xfinity-email/
Server: 'smtp.comcast.net'
Windows Live Mail Error ID: 0x800CCC6F
Protocol: SMTP
Port: 25
Secure(SSL): No

original title: I am receiving the error message below when trying to send e-mail via Windows Live.  I can receive e-mail, but can not send them, even to myself.

 

An unknown error has occurred.

Subject ''
Server Error: 554
Server Response: 554 omta01.westchester.pa.mail.comcast.net comcast Port 25 not allowed - http://customer.comcast.com/help-and-support/internet/email-client-programs-with-xfinity-email/
Server: 'smtp.comcast.net'
Windows Live Mail Error ID: 0x800CCC6F
Protocol: SMTP
Port: 25
Secure(SSL): No

The server for account "Yahoo" returned the error "[SERVERBUG] AUTHENTICATE Unable to open mailbox; please try again later." Your username/password or security settings may be incorrect. Would you like to try re-entering your password?

When I re-enter my password, I always tick the box to "remember the password in the keychain".

Then Outlook connects but disconnects after a while. 

In general, the account is always disconnected after a long period of inactivity (say overnight).

Any tips?
Basically I have recieved my mail but cannot send any because my email is not passing the test to set up this account with my outlook software in a pop3 setting.   Send and recieve error stating .. none of the authentication methods supported by this client are supported by your server.
I get the following message:

Server Error in '/Calendar' Application.
Runtime Error
Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.

Details: To enable the details of this specific error message to be viewable on remote machines, please create a <customErrors> tag within a "web.config" configuration file located in the root directory of the current web application. This <customErrors> tag should then have its "mode" attribute set to "Off".

<!-- Web.Config Configuration File --> <configuration> <system.web> <customErrors mode="Off"/> </system.web> </configuration>

Notes: The current error page you are seeing can be replaced by a custom error page by modifying the "defaultRedirect" attribute of the application's <customErrors> configuration tag to point to a custom error page URL.

<!-- Web.Config Configuration File --> <configuration> <system.web> <customErrors mode="RemoteOnly" defaultRedirect="mycustompage.htm"/> </system.web> </configuration>

PLEASE HELP! I've looked this issue up online for the past couple of days and cant find a solution :( 
Can anyone tell me why I can not send out emails and keep getting this error message?
Thank you in advanced, Mag