SMTP Error 522, encountered in PHPMailer or Jenkins, arises when the recipient's email server declines the inbound email due to diverse factors. These may include an incorrect recipient address, a saturated mailbox, technical glitches within the recipient's email server, or the sender's IP address being blacklisted.

What are the cases covered in SMTP Error 533?

1. Case 1: "522 5.1.0 recipient@example.com: Recipient address rejected. Please verify the recipient's email address."
2. Case 2: "522 5.2.2 recipient@example.com: The recipient's mailbox is full. Delivery temporarily suspended."
3. Case 3: "522 5.7.0 recipient@example.com: The recipient's email server is experiencing technical issues. Delivery delayed."
4. Case 4: "522 5.7.1 Sender IP address is blocklisted. Email delivery denied. Please contact your email service provider to resolve the issue."

What's Causing This Error

• SMTP error 522 is often triggered when the client's IP address is found on a blocklist maintained by the recipient's email server or due to the server's security protocols.
• The blocklisting of IP addresses commonly stems from engaging in activities deemed malicious or suspicious.
• Sending bulk emails or conducting marketing campaigns are among the primary actions that can lead to an IP address being blocklisted.

Solution - Here's How To Resolve It

• To address this problem effectively, it is imperative to verify with the recipient's email server whether the client's IP address is flagged on any blocklists or obstructed by security measures.
• If the IP address is identified on a global or public blocklist, the client should commence an appeal process to request its removal.