When prompted with an error when trying to access WAC from other browsers saying the site is not secure.
Root cause: A self-signed certificated option was selected during the first installation
Uninstall WAC, and on the WAC Installation page - Select the second option and - specify the thumbprint and click on install.
And click on Install. This should fix the issue.
Other Possible problems – http://bit.ly/2tqsNGp