After sending emails through the Communication module, you view the mailing's reports. You notice there are many email addresses on the Soft Fail Report. The Failed Reason is IP XXXXXXXXXX is blocked by EarthLink. Go to earhtlink.net/block for details.
Note: This solution could be utilized for other email providers other than Earthlink
First, ensure the email addresses being blocked are valid email address.
If the email address/es are valid, Chat With Support and reference this article. . Include the following information in your case: