Will not start and flashing security light

Let's try a couple things unless you have done this so, please run through this guide and tell me if none of it works:

https://www.2carpros.com/articles/how-to-reset-a-security-system

If it doesn't then we may have an issue causing the theft system to be on. So that means we need to scan for codes and find out if there are issues.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

This vehicle is basically a Dodge Caravan so we should have some codes that will point us to a body issue which means they will be B codes.

So, let's start with this info and go from there.

Thanks