There are two different ways of getting in touch with the developers:
You can subscribe to the list via the web interface.
This mailing list is for general discussion on potfit. Here you can post your questions, discuss with other users, request new features, submit bug reports, …
Subscribers to this mailing list can review their subscription settings here.
The https://github.com/potfit/potfit page provides an issue tracker which may also be used to submit general questions, help requests or bug reports.
When asking for help please provide as much information as possible. This includes:
If possible you may also provide the used input files, which usually helps a lot.