SMTP Error 422 is a permanent or "5xx" error code returned by a mail server, indicating the rejection of an email message due to the recipient's mailbox or account being over quota or exceeding storage limits. This error denotes that the recipient's mailbox cannot accept new messages until the storage issue is resolved.

What's Causing This Error?

SMTP Error 422 can be attributed to various factors, including:

1. Server Congestion: The mail server handling a high volume of incoming email traffic, causing delays in processing new messages.
2. Greylisting: Some mail servers employ greylisting as a spam-fighting technique. Initially, an unknown sender's email may be rejected with a 420 error, requiring the sending server to retry after a delay for acceptance.
3. Temporary Server Issues: Server hardware, software problems, network issues, or other transient factors can lead to SMTP Error 422.

How to Resolve SMTP Error 422 - Step-by-Step Solution:

To address SMTP Error 422, follow these steps:

1. Contact the Recipient: If encountering SMTP Error 422 while sending an email to a specific recipient, reach out to them through an alternative method (e.g., phone) and inform them of the storage issue. The recipient needs to free up space in their mailbox.
2. Archive or Delete Emails: The recipient can alleviate storage issues by archiving or deleting old emails, especially large attachments or unnecessary messages.
3. Increase Mailbox Storage: Contact the email provider or administrator to request an increase in mailbox storage capacity if persistent storage issues occur.
4. Empty the Trash or Deleted Items Folder: Ensure that the recipient empties the "trash" or "deleted items" folder to free up space.

SMTP Error 422 Examples:

• "422 4.2.2 Mailbox over quota. Unable to accept new messages until space is freed up."
• "422 5.7.0 Mailbox storage limit exceeded. Archive or delete old emails to resolve."
• "422 5.2.3 Recipient's mailbox is full. Contact recipient to clear space for new emails."

SMTP Error 422 in phpmailer Instances & Examples:

• Case 1: "SMTP Error 422 - Server congestion in phpmailer."
• Case 2: "SMTP Error 422 - Greylisting issue in phpmailer."
• Case 3: "SMTP Error 422 - Temporary server issues in phpmailer."

SMTP Error 422 in Jenkins Instances & Examples:

• Case 1: "SMTP Error 422 - Server congestion in Jenkins."
• Case 2: "SMTP Error 422 - Greylisting issue in Jenkins."
• Case 3: "SMTP Error 422 - Temporary server issues in Jenkins."

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