Description – Backup process will be aborted if the IMAP is disabled in your Google Admin Console. It is essential to enable IMAP to allow the backup of your emails.
How to enable IMAP?
Login to domain’s administrator account, click on the gear button available in the right top corner of the mail box and select the “Settings” option as shown below.
Choose “Forwarding and POP/IMAP” as shown below. In the IMAP Access field, check “Enable IMAP” option.