You may receive the below error message wgen setting up a Web Application Proxy (WAP) for ADFS on Server 2012 R2
Event ID: 12021
Task Category: None
Computer: <server name>
Web Application Proxy could not bind the SSL server certificate. Error: Cannot create a file when that file already exists.
All other configuration settings were applied.
Certificate thumbprint: <thumbprint id>
Host name: <fqdn of adfs>
The WAP still works with this error and we have received it when using a wildcard certificate. Hopefully this will save someone some time as we have rebuilt a server multiple times and still receive the above error.