I'm working on UAT environment setup.

We recently hosted a SharePoint hosted app with SSL certificate installed.

When the app is running in UAT in app web, the web address is generating a Certificate error "mismatched address - the security certificate presented by this website us issued by a different website's address.

This problem might indicate an attempt to fool you or intercept any data you send to server.

We recommend that you close this webpage"

We're trying to identify the cause but have no idea.

Appreciate if you can help us in this regard.

I had similar issue on creating SSL certificate on my Dev environment. Can you make sure there is no unused or previously created SSL certificate in the environment by running the PowerShell command below:

Get-SPTrustedSecurityTokenIssuer

If it returns any, you may want to remove that and then re-add a new SSL certificate. There are scripts available online to create a new SSL