429 (Too Many Requests)

I have a custom-built contact form at the bottom of the page. When I submit the form twice in a row, it works — the data is submitted and any errors are shown correctly. However, on the third attempt, a console error appears, and the submit button stops working for a long period. After a few hours, the same issue happens again.

Error:

tccl-tti.min.js:1

       POST https://domain.com/wp-json/contact-form-7/v1/contact-forms/837/feedback 429 (Too Many Requests)

1. Response {type: ‘basic’, url: ‘https://domain.com/wp-json/contact-form-7/v1/contact-forms/837/feedback’, redirected: false, status: 429, ok: false, …}
   1. body: (…)
   2. bodyUsed: false
   3. headers: Headers {}
   4. ok: false
   5. redirected: false
   6. status: 429
   7. statusText: “”
   8. type: “basic”
   9. url: “https://domain.com/wp-json/contact-form-7/v1/contact-forms/837/feedback”
   10. Prototype: Response

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