As far as I see you use the "Turn WordPress to wpForo" option in Forums > Settings > General Tab. Am I right? Please let me know why do you use this option? Do you know all disadvantages of this option? If you use this option, all your non-forum pages should be added in according textarea to be accessible. Please read the documentation attentive: https://wpforo.com/docs/root/getting-started/forum-page/turn-wordpress-to-wpforo/
So the contact page URL should also be added in "Exclude Page URLs" textarea.
I'd recommend use the regular way to set forum on home page rather than the "Turn WordPress to wpForo" option, this option turns off all non-forum content on your website frontend.