Fixing "Authentication failed" or being unable to add an account (iCloud, Office 365 / Microsoft, Gmail, Yahoo)

If Airmail shows an "Authentication failed" message, keeps asking you to sign in, or will not let you add or re-add an email account (iCloud, Office 365 / Microsoft, Gmail or Yahoo), it usually means the account's saved login (its authorization token) has expired and needs to be renewed. The steps below resolve this in most cases.
Before you start: make sure Airmail is updated to the latest version from the Mac App Store (App Store > Updates), that your Mac is connected to the internet, and that the date and time are set automatically.
Step 1 - Re-authorize the account. Open Airmail and go to Airmail > Settings (Preferences) > Accounts. Select the account that is failing and choose to sign in / re-authenticate, completing the login on your provider's official sign-in page (Apple, Microsoft, Google or Yahoo). This refreshes the expired token.
Step 2 - If it still fails, remove and re-add the account. In Settings > Accounts, remove the affected account, then use the + button to add it again and sign in through the provider's secure login. Removing an account from Airmail does not delete any of your emails from the server.
Provider-specific notes. iCloud and Yahoo often require an app-specific password: generate one in your Apple ID or Yahoo account security settings and use it when prompted. For Office 365 / Microsoft accounts provided by a company or school, your IT administrator may need to approve Airmail's access before sign-in can complete. For Gmail, make sure you complete the Google sign-in and grant access when the Google page appears.
Still need help? Reply to us in chat with your email provider, your Airmail version, your macOS version and the exact wording of the error message, and our team will be glad to assist further.

Updated on: 06/20/2026