System error (Failure): This error indicates that G Suite failed due to an outage or corrupt data.
We recommend the following:
- Wait and resubmit. This may have been a temporary failure.
- Log in to the mailbox. Check that it is not full. Browse to the offending folder.
- Corrupt content may be causing the issue. Consider filtering the folder. How do I filter a folder?
- Connect an IMAP client and reproduce the error. Then contact Google support.