I would like to know which is the best/easiest way to build a token based authentication that can validate the token on multiple instances.

I have a service that have just two credentials (inside appsettings, really simple), should generate a token with a different Role for each one, which is going to authorize some access using the Authorize attribute.

Right now I'm using ASOS, but I'm having some problems validating the toke when I have more than one instance running, so would like to change to a simpler authentication process.

Most of the implementations looks more complicated than I need for this case, does anyone know a better way?

Thanks.