Field Validation issue- Normally appearing on page and now only at submission

Since a week, my Eloqua forms on my website are not working as usual. Normally, I would see an error on the form if someone had forgotten to complete a required field and now it only appears after submission which is not very user-friendly.

You can test by completing this form using test in the email and miss a required field.

https://www.internationalsos.com/magazine/building-a-sustainable-travel-strategy-in-an-ever-changing-mobility-landscape

Can someone help?

thanks.

Emilie