Sometimes you get the error message as “550 Message rejected because (PC Name) IP address is blacklisted” in your outlook where you have configured your email account. This message appear when you try to send a mail from your mailbox. Screenshot of the error message is as below,


The problem is with your account setting where you need to provide the proper port number in the outgoing server request (SMTP). Below is the screenshot from my outlook where you can see that the default port for incoming server is 143 and for outgoing server is 25. You need to know whether your server requires any authentication for outgoing mails. If yes, then what is the port number for the same.

Change the port number and test your account setting.


  1. Go to the “Account Setting” under the Tools section and change your email account setting.
  2. Click on the “More Settings” shown above. One pop up will appear (same as above), then under the Advanced tab.
  3. Change the port number as your server authentication port number and click on OK.
  4. Test the account setting by clicking on the “Test Account Setting” button on edit screen (screen where the more setting option was available).
  5. Once the testing is successful, You are done otherwise check your account setting again.

Let me know in case you found some other issue related with Microsoft Outlook.

By Sanjeev Mishra

Sanjeev Mishra is a professional blogger and an Internet Marketing Consultant based in India. He has built the Internet Techies to provide you updates in technology and web application area.

Leave a Reply

Your email address will not be published. Required fields are marked *