What does the “UID SORT: Internal Error” mean, and how do I resolve it?

The "UID SORT: Internal Error" indicates your account’s mail storage is exceeded (e.g., 40.01 GB of 40 GB used). See https://us.cloudlogin.co/help/view-article/?id=527 for details. To resolve:

1. Purchase additional mail storage at https://us.cloudlogin.co/orders/services/?filter=mail_space.
2. Delete messages via the File Manager at https://us.cloudlogin.co/filemanager/#/mail, focusing on /cur subfolders.

Check your largest mailboxes and remove unnecessary messages to free space.