I upgraded from EE2 to EE3. I had Devdemon tagger add-on, so I also had to upgrade it to the newest version (4.0.0) in order to be compatible with EE3.
The problem is that whenever I add a tag to an entry (new or existing) it doesn't get saved. When I hit Publish it seems like it is there, but when I go back to the entry the added tag isn't there. So in the front end there are no tags showing.
The entries added before I did the EE upgrade DO have their corresponding tags.