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Signup email form 403 issue

  • January 16, 2026
  • 3 replies
  • 61 views
P
Contributor I
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We are getting consistent 403 Forbidden errors on all Klaviyo onsite endpoints
(client/subscriptions, profiles, events).

This happens on desktop and mobile, across multiple networks.
No emails are added, and the signup form spins infinitely.

This appears to be a DataDome false-positive block.
Could you please reset / whitelist our account or advise on remediation?

Store: prettyinsideout.ca
Company ID: XqkFfT

 

Best answer by Kim from Cadence

Hey ​@PrettyInsideOut, can you confirm whether you have a public key referrer allowlist defined? 403s on these endpoints might indicate that you have this set up in a way to not allow your domain prettyinsideout.ca. 

Here’s a guide with more details - https://developers.klaviyo.com/en/docs/create_public_api_key_allow_list

Cadence / Book a demo

3 replies

Kim from Cadence
Partner
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Hey ​@PrettyInsideOut, can you confirm whether you have a public key referrer allowlist defined? 403s on these endpoints might indicate that you have this set up in a way to not allow your domain prettyinsideout.ca. 

Here’s a guide with more details - https://developers.klaviyo.com/en/docs/create_public_api_key_allow_list

Cadence / Book a demo

Kim — Founder @ Cadence | Helping brands automate recurring campaigns (daily, weekly, monthly) | Happy to connect! | https://cadencecampaigns.com
js24r
Contributor I
  • js24r
  • Contributor I
  • January 23, 2026

Hey ​@PrettyInsideOut, can you confirm whether you have a public key referrer allowlist defined? 403s on these endpoints might indicate that you have this set up in a way to not allow your domain prettyinsideout.ca. 

Here’s a guide with more details - https://developers.klaviyo.com/en/docs/create_public_api_key_allow_list

Cadence / Book a demo

Hey ​@cadence having this exact issue, allowlist properly defined, no form submissions works on the site just infinite loading symbol and an ocassional “An error occured when submitting. Please try again later.”

Any solutions you’re aware of?

Kim from Cadence
Partner
Forum|alt.badge.img+12

​@js24r, happy to take a quick look over PM if you want to send over a screenshot of your allowlist and the problematic URL on your site.  

Cadence / Book a demo

Kim — Founder @ Cadence | Helping brands automate recurring campaigns (daily, weekly, monthly) | Happy to connect! | https://cadencecampaigns.com

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