When I opened the database in DT3 and was not asked to enter a password, I am sure I have set password protection. Is there anything wrong with it?
Welcome @junmu
There is nothing wrong with it. It no longer works that way. The username and password are used for sync authentication only now. This is clearly noted in the File > Database Properties.
If you want a secure database, create an encrypted database via File > New Encrypted Database.
PS: This is covered in the built-in Help (which is also part of the beta test). See the Documentation > Windows > Database Properties. And yes, there’s a typo we will be fixing. 