Usually it is the connection between acrylic tube and that connector. Check for leak there. Some people add silicone there to stop the leak. Do you have photo of the connection and tubing. I prefer containers that use John Guest fittings. The acrylic tubing should fit in John guest fitting, and there is also barbed fitting into John guest as well.
Just a note: on the containers, the lid should not be air tight, so it doesn’t create vacuum as more liquid is drawn out.