According to the Drupal security advisor (https://www.drupal.org/sa-contrib-2021-006), it's advised to upgrade the samlauth module to 8.x-3.1. But after the update, the Acquia SSO returns error with samlauth module.
Call to a member function getAccountName()
If you are still unable to logged in after module update, then kindly delete your account from your website and again login through SAML. It will resolve the login issue.