Tag Tool has a red circle with line thru it - wont work

I’m going thru the video series in sketchup school on importing and working with CAD files.
I’m seeing the pencil is not shown as assigned to untagged, there is no pencil icon. Secondly following along the video series of creating a tag and using it to assign to all untagged, the tool is inoperable. I’ve had this same issue when trying to use in general.
Can’t find any topic that helps me resolve this/understand what’s going on.
Thanks

Try these:
Tags, Square One
Tags, Skill Builder