The Sign-in methodssection on Settings > Security shows your primary sign-in method and, when applicable, a backup password. Every Laureo account is pinned to a single primary method — Google, Microsoft, or email and password — and that is the method you sign in with from then on. See Primary and Backup Sign-In for the why.

If your primary sign-in method is email and password, you can link oneOAuth provider — either Google or Microsoft. After linking, that provider button on the sign-in page works for you, but your account is still email-primary and the OTHER provider stays hidden. Linking a provider also creates an integration token that the inbox and calendar use, so you do not need to connect the integration separately. See Primary and Backup Sign-In.

OAuth-primary accounts are fully functional — you do not need a password. But adding a backup passwordgives you a second way in if your provider has an outage or your Google / Microsoft account changes. The action is on the Password card at the top of the Sign-in & verification section, and it routes through the forgot-password flow because it requires verification by email.

• "This is your primary sign-in method and cannot be unlinked" — The primary-provider guardrail. To change your primary, an administrator must run the migration flow.
• "This is your only sign-in method" — The zero-methods guardrail. Add a password or link another provider before unlinking.
• "Failed to start link flow" — The provider redirect could not be constructed. Try again; if it persists, check for browser extensions blocking cross-site requests.
• "Failed to unlink identity" — The backend rejected the unlink, usually because the request ran after the zero-methods count would have been violated (race condition). Reload the page and try again.