I am trying to build mailman. I assume these are the instructions: http://wiki.list.org/HyperKitty/DevelopmentSetupGuide
Although the page is for Hyperkitty, I assume that others will be built in the same way since that is the only page I could find.
I can't clone the repositories from gitlab. It gives me the following error: Permission denied (publickey). fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.
How do I solve that error? Also, am I following the correct build instructions?