What's Causing This Error
Multiple reasons can cause this error. The most common causes for this error are:
- Configuration errors.
- The sender's domain is present within the blocklist.
- Invalid recipients.
Solution - Here's How To Resolve It
To resolve this error, the user must ensure that they address the following potential causes:
- Ensure that the configuration does not contain any errors.
- Ensure that the sender's domain is not present within any blocklist. The recipient's email server administrator can attempt to check if the sender's domain is blocked.
- Ensure there aren't any invalid recipients within the list of email addresses. It may also include duplicate email addresses.