MIDI and Musical Typing stops working mid project

While working in Logic, my MIDI keyboard and Musical Typing stops generating sound. Logic detects a MIDI input in both cases (visible in the display) but no audio. It works completely fine, and suddenly stops working. If i start a new project it works as normal, but if I go back to the old project the issue persists.

A workaround I did was importing all project settings into a new project. However this was a tideous process, and messed up my routings and structure. Any idea how to fix this weird issue?

Logic Pro 10.7.9