WordPress Form Submissions Failing Only for Real Visitors – No Errors in Logs

I’m experiencing a persistent issue where forms fail to submit for real visitors, but work fine when tested manually. This happens across multiple hosting providers (SiteGround, Hostinger, Hetzner, etc.), themes, and form plugins (Gravity Forms, Elementor Forms, Ninja Forms, etc.).

Issue:

Visitors click the submit button, but the form does not process their entries. No errors appear in console logs, server logs, or Gravity Forms logs. Form submissions succeed when manually entering details, but fail when autofilled via URL parameters (e.g., ?email=test@gmail.com&fname=John). Happens on fresh WordPress installations with only Gravity Forms and a page builder installed. What I’ve Tried:

• Disabled caching (Cloudflare, WP Rocket)
• Disabled security features (ModSecurity, firewalls, security plugins)
• Switched hosting (Hetzner → Hostinger → SiteGround)
• Tried multiple form plugins (Gravity Forms, Fluent Forms, WPForms, Ninja Forms)
• Used a fresh WordPress install on a subdomain, but the issue persists
• Tested with and without ad blockers – no difference
• Checked Hotjar recordings – visitors click submit, but the form hangs
• Plugin support (Gravity Forms, Elementor) couldn’t replicate the issue.

Additional Notes:

• Plugin support (Gravity Forms, Elementor) couldn’t replicate the issue.
• No PHP errors are logged.
• Hotjar recordings show users clicking submit, but the form does nothing.
• This issue existed before Hotjar was installed, so it’s not a conflict.
• Debug logs don’t show blocked requests.
• The issue seems to happen universally regardless of form, page builder plugins, or themes

Additional Clues:

Issue occurs before submission is processed (even with simple confirmation messages instead of redirects). Form submissions don’t even register as clicks in Hotjar for Elementor and Formidable forms. The issue happens for almost all real visitors, not just specific ones. No 403/404 errors in server logs, but POST requests from real users don’t seem to reach the server.

How visitors access the form:

1. I send an email with a Pretty Link (Prettylink1).
2. Prettylink1 redirects to another Pretty Link (Prettylink2).
3. Prettylink2 redirects to the final form URL.
4. Visitors land on the form page but fail to submit unless manually interacting with fields.
5. Even when testing direct visits (bypassing Pretty Links), the issue still happens

Possible Causes? JavaScript not executing properly for real visitors? AJAX requests getting blocked silently? ModSecurity filtering requests without logging errors? I’m out of ideas at this point—has anyone encountered anything similar or have suggestions for further debugging?