How to configure MySQL Router on two application servers?
I managed to resolve the issue and I am posting what resolved it for me in case someone else might run into this dilemma.

The resolution was to run mysqlrouter with the --bootstrap option on both app servers but I was missing the --name parameter (which is a bootstrapping option). The --name parameter gives a symbolic name to the router instance and since I was not passing on that parameter it gave it a blank name or ' '. Like ' ' router instance already existed then when trying to bootstrap on server 2 it was failing because ' ' router instance already exited. The trick here is to give each router instance a different name. All the examples that I found online only show you how to configure the router for a single instance not for a double instance that is why I was making the mistake on not giving it a name. 

Anyway, I hope this helps someone.