In this image, the Ramp Agents are complaining they cannot enter a secure area. You note I have a manned Security Checkpoint (Employees only). Because of this, some of my areas, which require Ramp Agents (such as the Baggage Bay) are going unmanned. The brown floor area is the secured area.
Could you send a screenshot of your airport with zoning enabled?
Maybe the security zone where your ramp agents are at isn’t connected to the baggage bay,
keep in mind that they need zoned sidewalks and road crossings too.