SharePoint Designer 2013: The server could not complete your request. For more specific information, click the Details below

I found this issue in SharePoint Designer 2013 when accessing your SharePoint sites.

It will pops up below message box repeatedly until I force to kill the SPDESIGN.EXE from the Task Manager. The message “The server could not complete your request. For more specific information, click the Details button.” is very vague and does NOT tell you what is the root of error.

1. Enable Anonymous access in IIS for you Default SharePoint site and
2. in bindings don't forgot to delete additional binding if any.