While installing the Web Adaptor it displays the following error:
"Error 2878: On the dialog WebSiteList the control ListBox1 has a possible value: Default Web Site, 80,1. This is an invalid or duplicate value."
This workaround installs the ArcGIS Web Adaptor normally. It is also possible to run the Web Adaptor install silently from the command line to work around this issue. If it is preferred to install the Web Adaptor silently rather than change settings in IIS, please see the Related Information section at the end of this article.
The issue occurs when there are multiple bindings on the same port on a single web site in IIS, or there is multiple web sites with the same port binding. The Web Adaptor installer fails to complete and returns the error.
To workaround this issue, the existing port bindings can be removed or edited and then changed back after the install is complete.
Note: After the Web Adaptor install is complete these can be changed back.
To remove the binding:
To edit the binding:
If there are any other web sites, repeat steps 2 through 4 to make sure that there are no duplicate bindings with the same port number and that the different sites don't have any bindings on the same port number as another site.
Complete the install of the Web Adaptor. There should be no error during install. If there is an error, please repeat steps 2 through 5 and verify that no two sites have the same bindings and that no site has multiple bindings on the same port.
If necessary, go back into IIS Manager and change the port bindings back to their previous state.