Cant select CODE feature in Next-Gen project

[dave_gssavionics_com]

Hi, I've created many JIRA projects in the past and always used the Bitbucket integration with no problem.

Now I've created a new Next-Gen Software project, but dont see the usual "Add Branch" option on my Issues - I've tried enabling the "Code" Feature for this project, but the toggle button just immediately resets.

Any ideas ?