This is just a small CSS conflict with the theme or other plugins. Please leave the example URL where we can see the wpDiscuz plugin activated to allow us to debug the issue and provide a solution for you.
In case you want to say thank you! 🙂 We'd really appreciate if you leave a good review on the plugin page. This is the best way to say thank you to this project and the support team.
Please navigate to Dashboard > wpDiscuz > Settings > Styles & Colors admin page and enable the "Load Font Awesome css lib" option.
Delete all kinds of caches before checking.
In case you want to say thank you! 🙂 We'd really appreciate if you leave a good review on the plugin page. This is the best way to say thank you to this project and the support team.