Error: SMTP Error 554

What's Causing This Error

SMTP error 554 indicates that the mail server did not accept the email. Several reasons typically cause this error:

1. Invalid Recipient Address - There are invalid recipient email addresses; in rare cases, the recipient email address may have been suspended or disabled.
2. Blocklisted IP Address - It indicates that the sender's IP Address might be within a blocklist; this may be because the sender can get flagged for sending spam or bulk emails.
3. Bad DNS Records - The recipient's email server rejects emails due to issues that it may see in the email server's DMARC, SPF, and DKIM for validating the sender.
4. SPF Record - The recipient may have configured SPF (Sender Policy Framework) to drop unwanted spam domains. The policy set by the recipient may be blocking the emails from being accepted by the recipient.
5. DKIM Record - DKIM records help a mail server verify whether a sender is legitimate. Some email servers reject emails if the sender doesn't have DKIM configured.
6. DMARC Record - DMARC records also help a recipient verify the authenticity of an email and its source; some email servers may reject emails if they identify invalid DMARC records.
7. Sender Flagged As Spam - Most email providers configure custom blocklists to drop potential spam users and domains; this can mean that the email address or domain falls into a blocklist, and the recipient drops all emails.
8. Email Violation Policy - Email service providers specify policies to ensure that emails must follow a particular set of criteria. The recipient can drop emails that are not according to the set policy.

Solution - Here's How To Resolve It

1. Invalid Recipient Address - Check if the email address(es) you are attempting to send the emails to is valid and if there are no spelling mistakes.
2. Blocklisted IP Address - The user must remove their IP Address or domain from public blocklists. You may use tools such as MXToolBox to verify if your domain is within any of these blocklists; this is possible by informing the blocklist owners.
3. Bad DNS Records - Make sure that the "DMARC," "SPF," and "DKIM" records configurations are valid.
4. SPF Record - Check with the recipient to verify if the email server or domain contains an SPF record and if so, check if this configuration blocks your domain.
5. DKIM Record - Check if the sender's DKIM record is valid.
6. DMARC Record - Check if the sender's DMARC record is valid.
7. Sender Flagged As Spam - Check if the sender's domains are marked as spam by the recipient or the recipient's email provider/server.
8. Email Violation Policy - Check with the recipient's email violation policy and adhere to the policy to resolve this issue.