NET::ERR_CERT_AUTHORITY_INVALID only on some PCs

[Kandrina]

We are using a hosted webserver (by all-inkl) with wordpress, now one of our cusomers sent a screenshot of this error message, but on all our PCs it works perfectly fine, with the same browsers, he was using IE 11 and Google Chrome V 74.0.3729.169

My domain is: https://www.contakt-edv.com

My hosting provider, if applicable, is: all-inkl

I can login to a root shell on my machine (yes or no, or I don’t know): no

I’m using a control panel to manage my site (no, or provide the name and version of the control panel): no

[JuergenAuer]

Hi @Kandrina

@Kandrina

My domain is: https://www.contakt-edv.com

I don't see a problem ( https://check-your-website.server-daten.de/?q=contakt-edv.com ):

The domain has a very good Grade B, so both connections (non-www + www) are secure, there are correct redirects, no http result.

The certificate is ok:

CN=contakt-edv.com
	25.03.2019
	23.06.2019
expires in 31 days	contakt-edv.com, www.contakt-edv.com - 2 entries

and the chain is correct:

Chain (complete)	
	1	CN=contakt-edv.com
	2	CN=Let's Encrypt Authority X3, O=Let's Encrypt, C=US

And there are no mixed content errors ( https://check-your-website.server-daten.de/?q=contakt-edv.com#html-content ). There are some Subresource Integrity definitions possible, but that's not a problem that would create a client message.

Looks like this customer uses a firewall or Anti-virus software with a SSL inspection. So that software creates an own certificate and is a Man in the middle.

But that's a problem of that customer, not of your website.

Can you share the screenshot? With the certificate informations?

There it should be visible if it is a Anti-Virus-Software certificate.

[Kandrina]

Thank you for the reply, i will ask our customer to send us a screenshot.