@1780yz You are facing an issue caused by the replacement of the Activity Stream application with the Notifications application, which happened in XWiki 10.9RC1. You have to get rid of the old plugin and make sure you have the new one. You can start from https://www.xwiki.org/xwiki/bin/view/ReleaseNotes/Data/XWiki/11.1/#HBackwardCompatibilityandMigrationNotes.
BTW, you question duplicates 10.8.1 to 10.9 Notifications macro doesn't work, please read that discussion.
Hope it helps!