Hello tommyt.
What happened is tied to Yahoo’s OAuth (authentication) system and how it manages app permissions for third-party email clients like Aqua Mail.
Yahoo periodically expires or revokes “tokens” that apps use to access accounts through secure sign-in (OAuth). These tokens are time-limited for security reasons, especially if:
1. Yahoo updates its authentication or privacy policies,
2. The app hasn’t refreshed the token recently,
3. There’s a change in the device’s system components (like Play Services, keyboard, or security modules), or Yahoo runs a security audit or account integrity check.
When that happens, Aqua Mail can no longer authenticate automatically, and Yahoo requires you to re-authorize the connection, which is why you were redirected to Yahoo’s login page to “grant permission to access email.” Once you re-approved it, a new token was issued, and Aqua Mail resumed normal operation.
This kind of re-authorization doesn’t affect all Yahoo-related domains (like sbcglobal.net or att.net) at the same time, because those use slightly different authentication endpoints. It also explains why other apps (like the native Amazon mail client) weren’t affected, they use their own tokens or a different connection type.
There’s no problem on your side or in Aqua Mail itself, this is expected behavior when Yahoo rotates or expires OAuth credentials. Unfortunately, Yahoo doesn’t send alerts about these events, so users only notice when access is interrupted.
Re-authorizing in Aqua Mail is the correct and only needed step. Once renewed, your connection should remain stable until Yahoo enforces the next token refresh, which may be months or even years down the line.
