This occurs when you try to access it from a US-IP.
Cloudflare lets you create custom error pages [1]. I would recommend making one for any geo-restricted pages. The benefit is that you can emulate your site theme and have an opportunity to explain the reasoning for the geographic restrictions.
Why do you feel the need to geofence it outside of the US? Where is the foundation based/registered? Where is the for-profit that you are the CEO of registered? How much is Signal getting for this?