Prevent multiple subscriptions and repeated emails with Hustle local list (embed

<span style=”font-size: inherit;”>Hello,</span>

I understand that double opt-in is only available via third-party services (Mailchimp, MailerLite, etc.) connected to Hustle.

However, with Hustle’s <strong data-start=”1300″ data-end=”1314″>local list, and <strong data-start=”1320″ data-end=”1344″>using the embed form, there is no verification: anyone can subscribe multiple times with the same email address, and an email is sent each time.

This behavior makes the feature almost useless, as the same inbox can be spammed endlessly.

My question: <strong data-start=”1576″ data-end=”1705″>how can I prevent an email from being sent every time a subscription is made with an email already present in the local list?

Is there a native option, a complementary plugin, or a filter to apply to block or group these subscriptions?

Thanks in advance for your advice!

The page I need help with: [log in to see the link]