How does a fountain pen pen work?
Well the ink cartridge has to be pierced. usually there is a little sort of needle like thing that the cartridge goes on top of and you have to press it onto it to break the seal to have the ink flow down to the nib. So open it and look to see if the cartridge has been installed correctly (removal is optional but can be messy so have napkins handy). Best to turn pen with nib upwards to allow ink to flow back into cartrdige. then see if it is seated properly to allow for the ink to flow out. Check the ink to see if it has dried too much. Should not have if it was sealed properly. Could be blockage in the pen ink channel, but that’s only in older not used much ones. That might need to be cleaned.