Reset keychain "login" password

When I want to use one of my digital certificates Keychain promts me to enter my "login" password. I have no idea what this is. I have tried my Mac login password, my Apple ID password and others, it didn't work.

I opened keychain access app and chose Reset Default Keychain, which created new login keychain. When i go to use my digital certificate it still prompts me to enter the old login password. Or maybe the new.. either way it does not work even with the new password i just set. It solved nothing. I don’t know what to do.

How can i reset my "login" password? How can I access my certificates?

Thanks