When signing up to be a halo insider, pressing “Link Steam Account” a window opens up and presents in big letters, " 
Application Error"
Going to close this off in favor of a single thread that can be used to track the issue
https://www.halowaypoint.com/en-us/forums/8f4648981f554a9d86527a5754966e89/topics/can-t-link-steam-account/686cabf9-506f-4c70-bbea-2cce99771c82/posts?page=1