Contact

Marionnet has no contact form: exchanges go through Launchpad, where they stay public and benefit everyone.

A defect, a crash

Report it on the bug tracker. Say which distribution you use, how you installed Marionnet, and what you did just before the problem.

Before writing, section 9 of the full installation guide (“When something does not work”) may already have the answer.

A question

Ask it on the project’s questions page.

In both cases a Launchpad account is needed; it is free.