Make sure your PokerStars client is running in English (PokerStars Client -> Settings -> Global -> Language -> English) otherwise the HUD may not attach to the table:
PokerStars Configuration GuideIf that doesn't get things going please
enable logging, reproduce this problem and then send your log file to us in a
Support Ticket. You can access the 'Logs' folder with the log file by clicking 'File --> Open User Data Folder' in the main PokerTracker 4 window and the file we need is the text file called 'PokerTracker4' or 'PokerTracker4.log' that is in that folder.