If you enable SSO but then can't log in using SSO, you can use the local login to regain access. This is only available to users with the Tenant admin user role. See our knowledge base article, Rescue URL for tenant administrators.
If your organization has a Google account, you can link it to your Applaud tenant, so your users are authorized and authenticated by your Google account. You need to provide your Google Client ID and secret to your Applaud tenant for this to work.
In addition to Applaud's user authentication, the system supports single sign-on to authenticate your users via Google. See Google's topic, Get started with Google Cloud.