The Requested Address Is Not Valid In Its Context

When trying to add the device “LG WebOS TV”, I receive this error:

My LG tv is connected to my network by ethernet. The Windows 10 computer where Home Remote Designer (ver. is running is connected by WiFi, but they are both on the same network.

I’ve actually been successful adding the LG WebOS TV device to a different .HRP file so I know that it can work. I just don’t know why it’s not working now.

Update: after closing the .HRP, then closing the Designer, then re-starting Designer and re-loading the .HRP I was able to add the device.