When accessing the PI Web Interface, sometimes even from the local machine, you'll be prompted with this authentication request.
After three attempts you will be left with:
This can be caused by multiple reasons, one likely cause is, that the PI Server OS language is a non English version.
- Open IIS Manager, on the Login PI Server.
- Click the PI Interface node and open the Configuration Editor.
- Check if the useAppPoolCredentials is set to True.
- Open the local group called Login PI Administrators.
- Make sure the Administrator and Domain Administrator are member of this group.
- Restart the PI Interface site with IIS.
It might be possible you still have to authenticate one more time when reopening the PI Interface, after making the changes.