Logic Pro 11.2 space bar does not start/stop projects

First check the key commands if start/stop is assigned to space bar.

Logic pro > Key Commands > Edit Assignements ...

If so, inspect the settings of control surfaces and try:

Logic Pro > Control Surfaces > Bypass All Control Surfaces

Logic Pro > Control Surfaces > Rebuild defaults

The FIRST thing I always tell my students to do when keyboard shortcuts don't work, is go to the System Settings, Keyboard, Keyboard Shortcuts, then click the Restore Defaults button. macOS shortcuts override application shortcuts. If something mistakenly gets reassigned in macOS, it'll mess up apps that use the same shortcut for something. This fixes issues most of the time.