Fortunately, I am close to the person who takes care about the LMU server.
Write an email to it@ifkw.lmu.de and include your old LMU email adress and your recent supervisor, so I can confirm that your new email address is actually yours. It should be possible to grant you access to the old account (if your recent login was not too long ago).
I couldn't share the project with anyone else outside the LMU server
There's an option to register guest accounts, but generally, a local university server is not suited very well to be used from different universities.