Matt Anderson said
1 year ago: Hmmm, so when you start typing your post, there isn’t a little graphic in the bottom left of a person with a plus sign?
I work with our customers in a closed group, and I know they have to be a member of the group in order to tag them in a post. Sometimes what I have done is find the person that you wanted to tag and send them a message asking them a question and get information that way.