The Office 365 module may log the following error:
Error in IMessage.GetRecipientTable: MAPI_E_NOT_ENOUGH_MEMORY ulVersion: 0 Error: There is not enough free memory to run this program. Quit one or more programs, and then try again. ulLowLevelError: 99 ulContext: 0
The above error usually indicates that a message has a large number of recipients or BCC recipients. If this is observed in a migration, please contact Support.