Hi Veronica,

Whatever is happening here is occurring "outside" of Laserfiche. Laserfiche web applications do not, to my knowledge, even support client certificate authentication out of the box.

If I'm understanding the scenario correctly, you have a Laserfiche Forms Portal instance that is publicly accessible. You have a link to a starting form on your organization's website. When an external user (applicant) clicks on the link, a browser prompt appears with "The website requires a client certificate".

I did a bit of research and found a few possible causes. 

1. The IIS site hosting the public Forms instance may be incorrectly configured to challenge for certificate authentication. See: Microsoft - "403.7 Forbidden: Client Certificate Required" error when you open an IIS webpage
2. It may be an error specific to the Safari browser and Apple keychains. The vast majority of search results I found for the issue were Mac-related. See: Safari error: This website requires a client certificate and Safari incorrectly demands to select an SSL client certificate
3. You may have a proxy in front of the Forms instance that is requesting certificate authentication.

Hope that helps. I would send this information to your IT team (if that's not you) and check if internal users on Windows computers using Chrome/Firefox/Edge get the same error when accessing the link.

Cheers,

Sam