Have you not spoken to him recently? If you haven't, you need to, otherwise he can't ping. If you have been speaking to him, save and quit and walk directly to his house while avoiding your other villagers, and he should ping you.
sometimes villagers dont ping if you haven't spoken to them for a few days. I would say talk to him once, save and quit, then run in front of him and he should ping.
another reason is if another villager ping'd you for catchphrases, greetings, etc, then marshal won't ping until a couple minutes have passed