Resolve WordPress-Mailchimp Email Issues

My opt-in pop-up on WordPress has stopped firing correctly and, even when it does, Mailchimp throws errors and the confirmation emails never reach the subscriber. I need someone to jump in, trace the fault, and get both sides talking again.

Here’s what I know so far: the emails should originate from both the site itself (for form notifications) and Mailchimp (for list-based automations), but I’m not sure whether an SMTP plugin is active or configured. The problem could be in the pop-up plugin, the Mailchimp API connection, DNS records, or the underlying email delivery settings—I just need it diagnosed and fixed quickly.

You’ll succeed when:
• The pop-up reliably appears, captures the address, and hands it to the correct Mailchimp list.
• Test emails sent from the site and from Mailchimp land in the inbox, not spam.
• Any SMTP or DNS adjustments you make are documented so I can understand the changes.

If you’re comfortable with WordPress email troubleshooting, Mailchimp API keys, and tools such as WP Mail SMTP, let’s get this wrapped up today.