Double Opt-In triggered despite being disabled in settings

[jeffpaul]

Describe the bug

The plugin is triggering the double opt-in process regardless of the opt-in setting configured in the plugin. Even when "Use Double Opt-In" is unchecked and the settings are saved, the plugin displays a double opt-in confirmation message after form submission and sends the double opt-in email to the subscriber.

Observed Behavior:

• After submitting the form, the plugin displays the double opt-in confirmation message.
• The subscriber receives a double opt-in email, even though the setting is disabled.

Expected Behavior:

• When "Use Double Opt-In" is disabled, subscribers should be added directly to the mailing list without a confirmation email.

Additional Context:

• Testing was performed in a sandbox WordPress account.
• Both the confirmation message and the double opt-in email were observed despite the setting being explicitly disabled.

Steps to Reproduce

1. Install and configure the List Subscribe plugin for WordPress.
   • [Installation instructions](https://mailchimp.com/help/connect-or-disconnect-list-subscribe-for-wordpress/)
2. Navigate to the plugin settings and uncheck "Use Double Opt-In."
3. Save the settings.
4. Use the subscription form on the front-end of the website to sign up for the mailing list.

Screenshots, screen recording, code snippet

1. Double Opt-In Setting Disabled

2. Form Submission with Double Opt-In Triggered

Environment information

No response

WordPress information

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[MaxwellGarceau]

First Thoughts

• Possible that there's a Mailchimp security setting in the Mailchimp API that's flagging similar emails while testing as suspicious and requiring double opt-in regardless of the Mailchimp WP settings. Will test with a range of real emails and fake emails to see if I can find any patterns with double opt-in.
• It's possible that this option in the user's Mailchimp account overrides the Mailchimp WP option. Will test with options in different configurations.

[jeffpaul]

Noting we should credit Nathan Tetzlaff for the issue report in any resulting changelog & credits update.

[MaxwellGarceau]

TLDR

• Bug confirmed: When subscribing a new user with the Mailchimp form a double opt-in email is always set
  • Same confirmation error message is received regardless of double opt-in settings in the Mailchimp account or Mailchimp WP settings
• Using the Mailchimp account webform the double and single opt-in settings work as expected

Next Steps

• Looking through the Mailchimp WP plugin code to ensure that single opt-in subscriptions are sent with status subscribed correctly - reference
• Ensuring that it's still possible to subscribe a user with single opt-in by setting their status to subscribed

If the above doesn't work

• Test with new (real) email addresses that wouldn't trigger spam or security validation rules
• Install the plugin a live self hosted WP site and test outside of local development (localhost) to ensure that spam or security rules aren't restricting based on a referrer URL from a local site

---

Testing Scenarios

No double opt-in set in Mailchimp WP or in Mailchimp account

Receive confirmation email

Double opt-in set in Mailchimp WP - NO double opt-in set in Mailchimp account

Receive confirmation email

Double opt-in NOT set in Mailchimp WP account - double opt-in set in Mailchimp account

Receive confirmation email

Mailchimp Native Web Form

Double opt-in disabled

Signing up with the native web form does not send a confirmation email if single opt-in is enabled.
https://10up.us9.list-manage.com/subscribe?u=552c76a95c758ead09f436258&id=a6913aba23

Double opt-in enabled

Receive confirmation email

[MaxwellGarceau]

Cause of bug - failing the condition check in mailchimp_sf_subscribe_body

error-in-conditional-check-causes-all-subscribers-to-be-pending.mov

Conditional check is setting new subscriptions to subscribed if

• $status is truthy (subscribed, pending, unsubscribed, etc)
• $doubleoptin is truthy

New users status is always false which is setting all new subscriptions to pending. The double opt-in condition also needs to be reversed.

wordpress/mailchimp.php

Lines 961 to 967 in 0b93ec3

	// single opt-in that covers new subscribers
	if ( false === ! $status && $double_optin ) {
	$body->status = 'subscribed';
	} else {
	// anyone else
	$body->status = 'pending';
	}

User has never been subscribed and double opt-in is disabled

User has never been subscribed and double opt-in is enabled

[jeffpaul]

@vikrampm1 when we get a release out for this, let's ensure we follow up via https://wordpress.org/support/topic/double-vs-single-opt-in/#post-18234911 so anyone following on wp.org are aware of the fix/release.