Cannot check out submodule from Bitbucket (SSH auth error)



Good morning all.

My project includes a submodule which I’m trying to checkout via my circle.yml file. Circle attempts to do this, but runs into an authentication error every time. This is despite having a user SSH key set up through Circle (though seemingly not visible on Bitbucket). The main project and this submodule are both hosted on Bitbucket repos belonging to the same user, so it seems very odd that one is accessible and the other is not.

I’m totally new to Circle; can anyone advise me?