YAHOO - Bounce Message Error Codes
Error codes starting with 4xxx are temporary problems. Error codes starting with 5xxx are permanent / fatal errors:
Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /domains/smtp-error-codes.info/public_html/includes/mysql_conn.inc:2
Stack trace:
#0 /domains/smtp-error-codes.info/public_html/bounce_error_codes_yahoo.php(41): include()
#1 {main}
thrown in /domains/smtp-error-codes.info/public_html/includes/mysql_conn.inc on line 2