WordPress pagination broken for page 2,3 with custom permalink. Redirects to baseurl

I have a forum installed with my WordPress site. My pagination does not work and redirects pages 2,3, or more to baseurl when they are on homepage. Here are the settings:

HomePage questions Pagination looks like this,

and redirects back to

For pagination on category and tag pages, it looks correct (https://example.com/forum/business/page/xxx/ & https://example.com/forum/qc-tag/business/page/xxx/)

Here is the .htaccess: