If the main pages that were assigned as Affiliate Pages are not working as you expected, first check if those were set properly.
You can learn more about setting those pages by reading this article.
Those pages may show up differently or not at all, even if you have set common slugs such as: login/, lost-password/, register/. In this case, WordPress may require an update on permalinks.
To avoid interacting with other scripts, we recommend that you set custom slugs for those pages (my-lost-password, uap-login, register-page, etc).