403 : Forbidden Error

I was working on the notebook and unexpectedly my browser closes, the link was

I believe that link you posted was for an ephemeral session that was meant just for you and is now gone. Public MyBinder launches are a free service and as such are temporary. The time out after 10 minutes of inactivity typically. The destruction of the sessions is part of the security and privacy considerations. See more pertinent details here and here. So save any work you do back to your local drive often and keep your session active while you work.

To launch a new session, go to GitHub - ipython/ipython-in-depth: IPython and Jupyter in-depth Tutorial, first presented at PyCon 2012 and click the `launch binder`` button.
That same series of notebooks is currently featured at the top of the list here. The launch badge is available there as well.

GESIS has a more persistent offering that requires a login. You can read more about it here and choose ‘Try it now’. If that was what you were using, maybe if you go there and log back in you can pick back up where you were working. However, you’d still be advised to save back to your local system any work you want to use in the future. Last I knew the persistent offering was also presently free and as such, you’d be advised to not rely always having access or the service being available forever.