I have a main site with multiple pages managed by WordPress. I also have a custom developed page on a different path, which is required by Google Auth as a callback. This page contains custom JS and works fine most cases. The callback by Google adds a whole plethora of parameters outside of our control, such as this example: 
https://<mydomain>
/ Home page managed by WP
/-- Sub pages managed by WP
/scheduler/googleCalendarRegistration.html <== custom page NOT managed by WP
In some cases WordPress interfers and throws a "404 - Not found error", when the custom page is called.
I need help either editing .htaccess or installing a plugin, so that my custom page is not funneled through the WP engine.