Getting 443 Forbidden Error on my custom module
_permission: 'TRUE' is not a thing unless you've defined a custom permission TRUE (and if you did, I'd advise you to change that). What you have is looking to see if a user has the permission TRUE - which I doubt any user has, and correctly denying access. If you want to grant access to the route for everyone, in all contexts, use _access: 'TRUE'. See Structure of Routes on d.o for more info.