The login page may require users to reset their passwords every time they log in. This issue is typically caused by a bookmark or link that contains extra information in the URL in the form of a query string. This information instructs the site that the user's password is incorrect or needs to be reset. This can be caused by copying the link from a Password Reset or Account Validation email.
Please update any bookmarks that direct to the site to use the homepage (https://[yourdomain]) and click the Sign In button or go to the admin page (https://[yourdomain]/admin).