Update is available as pull request and not as a release. Because of that plugin is missing from ACP.

@Julien-Heng Let us know any errors on the front-end or backend. Make sure a composer (like composer-default) plugin is active in the backend.

I am sorry @julian, it had nothing to do with user email. As I mentioned, I recently migrated from a phpBB forum to NodeBB while keeping the same website. My website uses WordPress to manage all user accounts, while phpBB forum had all the forum accounts linked to these users. I was supposed to map the WordPress user Ids (wp_id) with the phpBB user ids (phpbb_id) first before importing them into NodeBB which I initially did not do this correctly. However, it is all working nicely now. Thank you so much for your help!