php – PHPMailer w/SMTP to MailGun after a few hundred emails, get error: 451 Failed to parse header: malformed data; unexpected EOF

Using PHPMailer v 6.6.0 with SMTP to MailGun running PHP 7.4.28 & MySQL. The below code is in a foreach loop generating over 1,000 emails. Can send emails locally (using PHPMailer) without issue, but when sending externally via SMTP to MailGun, after a hundred or more emails have been sent, will have an SMTP communication … Read more