Source - Any, including G Suite > Destination - G Suite (Mail)
400 Bad Request
This is specific to individual mail item failures, visible in CloudM Migrate during migration via Progress > Import Failures, or the HTML report 'Import Failures' post-migration.
If a user migration fails outright with a similar error, it should be logged in a support ticket here.
This is a Google error and is typically caused by data that cannot be imported into Gmail for one of the following reasons:
- Blocked attachment types which are not allowed in Gmail per https://support.google.com/mail/answer/6590
- Emails containing virus attachments
- Emails not conforming to RFC 822 per https://www.ietf.org/rfc/rfc2822.txt
- The above are the most popular reasons for the error, and there is no solution to get the items into Gmail as it simply will not accept them,
- It can very rarely, however, also be a temporary error being thrown by Google. In which case, remigrating might resolve it.
It's important to note, that the more frequent this error, the slower a migration will run, as it will retry each failing message per the configuration step (2) Destination Platform - G Suite > Advanced Settings > Transfer Settings > Retry Count.