How do i do web filtering? sites added but not working 100D

[Creatish]

Hello using Fortigate 100D

I have added it in category overide and also web filtering

it works and let me on sometimes but on other times or a diffrent person they get this

An application is preventing Microsoft Edge from safely connecting to this site

"Fortinet" didn't install properly on your computer or network. Contact your organization to fix the issue.

NET::ERR_CERT_AUTHORITY_INVALID     I've tried using a hotspot to go outside the firwall and get certificate and uploading to fortigate but it give me an error suggesting i already have it?