Not receiving every records when submitted

Dear community,

One of our forms is having this issue: some people have been submitting the form properly BUT there is no trace of their record, nowhere. 

There is no record in the results section in Typeform, no email notification, no automation history in Zapier, no record in our Airtable base where the form is supposed to be sent.

According to Typeform support, it can be due to a network issue, ad blockers, VPN, firewall, proxy, etc, but they didn’t manage to reproduce the issue.

We also did a series of tests on different browsers, public and private modes, different devices, but it’s not concluding.

FYI: Those people don't come from one organization, they are individuals, most of them located in France, who are trying to apply to our program.

Is someone, by any chance, having the same issue? Any idea of solution?

Thanks in advance for your precious help.

Best,

Lucas