I created a website recently due to a supplier's requirements. They require a secured site, but the supplier contact keeps saying that they are unable to verify this. They have tried two separate browsers and both result in the same error. NET:ERR_CERT_AUTHORITY_INVALID.

I have contacted the web site hosting platform Zoho Sites and they were unable to recreate this issue as well, they also reaffirmed that the website's certificate is valid, that the website is secured, and that the link is running with HTTPS. I can't recreate what is happening on the supplier's end. Is it a company antivirus that is blocking it? Should I go and install a new certificate?

The website: cg-computers-llc.com

I'm stuck, any help would be greatly appreciated!