Cutover Migration from On Prem 2013 Exchange to Office 365 - MapiExceptionLogonFailed

Occasional Visitor

I am doing a cutover migration from on premise 2013 Exchange Server to Office 365.


Everything went fairly smoothly with setup and the migration run but will about 96 failures (only 14 successfully synced). The error is always the same:


Transient error MapiExceptionLogonFailed has occurred. The system will retry


After 600 tries it finally fails.


Did a bunch of research and ran PS commands on both sides to make my migration admin user have FullAccess rights. They do and still getting the same error for these users.


This is the command I ran. On the on-prem side I ran the command to allow ctadmin full rights. When that did not work I ran same command for on the Office 365 side and it still made no difference. User ctadmin is Domain Admin on the on-prem side.


Get-Mailbox -ResultSize unlimited | Add-MailboxPermission -User ctadmin -AccessRights fullaccess -InheritanceType all -Deny:$false


What am I missing.?! Appreciate any direction.



1 Reply

Hi Joel,


First of all, why are you doing a cutover, the best experience to the end users is Hybrid.


The error that you are experience maybe the fact of low resourses on AD.


Can you see if this article aplies to you ?