Problems can occur when syncing mailbox.org accounts with Google services: Google blocks access from mailbox.org. This issues an error message in the mailbox.org Office interface, indicating that the access data is incorrect.
The Google security settings display a notice indicating that a login attempt has been blocked. Access can be specifically allowed for a short period of time using a link (https://accounts.google.com/DisplayUnlockCaptcha). After this period has elapsed, you must attempt to subscribe to Google again. After this, the synchronization should function properly.
Google users who have activated ‘two-factor authentication’ must enter an ‘application-specific password’ for mailbox.org in the ‘Security’ area of the Google account settings. Use this password instead of the standard Google access data.
Note: We are not yet certain whether this method can be used to enable Google synchronization on a permanent basis. We have heard success stories from users for whom this method has worked permanently. Other users have reported that Google blocked access again after a certain period of time. We are still in the process of examining the issue more closely.