1. If you try to open IIS it gives this error message:
"A non-fatal configuration error occured. Not all available information may be displayed"
2. When you try and register a domain through helm you get this message:
"Unable to add new domain. Please try again or contact support."
This happens when the metabase for IIS gets corrupted. You should be able to use "metaedit" (a MS tool) to see what is in the meta base. Sometimes it's just one site that hasn't been added properly. You can see this as a site with no details underneath normally. If you find and remove the bad site you'll find that everything will be back to normal.
Link to tool -