I need to give access to the IIS user to a pfx certificate. The website is running under the App Pool under some user AppPoolUser. IIS automatically has the user name \"IIS
What works from me is my staging site is in network service (app pool) (deployment) and in my local is "applicationpoolidentity" (working copy)
just change it to applicationpoolidentity and run your winhttpcertcfg command