the error is telling us that the ACL profile of the user that you use to publish is not allowed to publish to topic ‘T/tab/Singelton/Sender’
The difference between Queue and Topic is only the additional “#P2P/QUEUE/” prefix when you want to use Queue.
So, I think first we need to confirm:
- the username
- the ACL profile of that username (by looking into the user details)
- the publish permission for that ACL profile has ‘T/tab/Singelton/Sender’ in the exception list
if possible, it might help to create a brand new username and a dedicated ACL profile so you can start with all allowed first, then disallow with exceptions as needed.