1) Try temporarily changing the WordPress theme to any default WordPress theme and check if the problem persists or not.
2) Make sure the forum permissions are set up correctly for the user group "guest".
3) If the problem still exists after the above two steps, please enable WordPress DEBUG in the wp-config.php file to display PHP notices, errors, etc., on the front page. This will allow you to check if your site has any errors or notices from the backend. https://wordpress.org/documentation/article/debugging-in-wordpress/

I think you've mixed boards with forums. I see you've created three boards. You should have one board and create forums in that board. Are you should you want to have three different and separate forum pages?

I'm having a few different issues. First one is the forum plug in itself doesn't seem to show on any web browser except for chrome and I'm not sure why/how to fix that. 

Additionally, I've added a screenshot, but when looking at the forum on my website there doesn't appear to be a log out option anymore?

Last one, when looking at plug ins enabled on Wordpress, wpforo has become three different drop down categories (WpForo, MAKE│NZ forum, and Forums)? And when trying to add new categories in any of the sections it doesn't seem to be coming through on the actual website.

I feel like there's probably going to be a really simple fix to these problems but I'm not sure what it could be.