I am having several errors displayed after installing the webadaptor onto my site. They all contain this error message "This error can be caused by a virtual directory not being configured as an application in IIS" all issues point to my web.config file. If it's of any help the first two of four errors are caused by these two lines so it leads me to believe that it is being caused by the aspnet_client. I have already made this into an application so I'm a bit lost at this point.
<authentication mode="Windows" />
<membership defaultProvider="AspNetSqlMembershipProvider">
Best Answer
After installing my web adaptor, iis is configured like this:
The apppool is configured like this:
In my web.config I have the two lines mentioned but I do not receive any error. I suggest you reinstall the webadaptor.