Ssl security not working with IIS for chrome

Welcome to the community @ispace

Could you explain more what you mean by "not fully secure in google chrome"? Is there a message on a browser? What version of chrome and on what system (android, iOS, ...).

As background, on Sept 30 a Lets Encrypt root certificate expired and has caused various issues. Your server is sending a proper Lets Encrypt "short chain" as is common with IIS now. Earlier, your server would have sent the "long chain" for best compatibility with older android systems. Below are a couple links with details. We will need more info about your specific problem to assist more. Thanks