Please make sure that you have the 888 software running in English, otherwise there may be a mismatch between the table name in the hand history files and that in the table window title. That would mean that the Hud could not match the two together and would not be able to attach to the table.
You may be able to change the language in the 888 software, but it may necessary to reinstall it in English.
If that does not resolve your problem please enable logging (Configure > Options) and restart PT4.
Play a few hands at a single table and take a screenshot
of the table window.
When you sit out create a Support Bundle
and attach that to a Support Ticket
along with your screenshot and the hand history file from the session.
By default the original hand history files will be moved to the Processed folder when you stop the import, which you can access via File > Open User Data Folder in the PT4 menu.