When ODM is migrating Microsoft 365 Groups linked mailboxes, this error is being flagged from ODM log :
Access is denied.
Check credentials and try again.
Cannot delete attachment.
ErrorCode = ErrorAccessDenied
Subject: XXX
Message ID: <XXX.apcprd03.prod.outlook.com>
Path: Inbox
Received Date: XXX
From: XXX
To: XXX
Migrate Groups
<M365 Group Name>
Since our ODM mail migration engine does not have any attachment deletion logic, this error may be a false alarm message which is likely to be returned by Microsoft EWS when performing mail migration, so it should be totally misleading & hence may be safely ignored according to our past experiences in dealing with this same error.
Meanwhile, kindly verify on your migration outcome at target to find out if those flagged out emails have actually got migrated with their original attachments to be intact.
If all affected mail items are already correctly being migrated, you can just safely move on to continue migrating your data.
However if any affected mail item happens to be not migrated, please let Quest Technical Support to know so that we can proceed to investigate further.
