Why This Happens: The “Not Secure” message appears because the site certificate doesn’t meet the latest security standards. Chrome, unlike Internet Explorer, treats it as invalid. From Chrome 58 onwards, only the subjectAlternativeName extension is used to match the domain name and site certificate, not the commonName . A registry fix was available but only worked up to version 65. More details can be found here. How to Fix It: You need to issue a new self-signed certificate for *.cloud.onebox.dynamics.com and update the website binding settings to use it. Step 1: Create a New Self-Signed Certificate Run the following PowerShell command as an administrator: New-SelfSignedCertificate -Subject "CN=*.cloud.onebox.dynamics.com,O=Microsoft Corporation,L=Redmond,S=WA,C=US" -DnsName "*.cloud.onebox.dynamics.com", "usnconeboxax1ecom.cloud.onebox.dynamics.com", "usnconeboxax1pos.cloud.onebox.dynamics.com", "usnconeboxax1ret.cloud.onebox....