Can not access dind through public ip address

[0YHR0]

As the instruction says, I set the public IP address in the .env file. But when I use the example: MyTinyToDo_MySql Docker to create an instance, it shows the error that can not connect to the publicip:2222.

We are currently working on a research project on Modeling information governance system using openTOSCA. We would like to get your help on this issue.
You can contact us via Webex.
Yang Haoran‘s email-address is: st180358@stud.uni-stuttgart.de
Asmita Chandrakar's email-address is: st180588@stud.uni-stuttgart.de