We also recommend that you bypass the network devices such as firewalls and reverse proxies during migrations in order to reduce source network latency and avoid frequent communication transient errors that would result in mailbox locks and slow migrations.
It would not work for other hybrid scenarios like Free/Busy, which cannot work with pre-authentication on EWS and Autodiscover. (*) Strictly speaking, for hybrid migrations and EWS/mrsproxy.svc endpoint, it would work if the device supported NTLM pre-authentication. This is required because, for example, Exchange 2010 cannot proxy to Exchange 2016 in order to move an Exchange 2016 mailbox to or from Exchange Online through an Exchange 2010 MRSProxy endpoint.
You cannot offboard a mailbox and a primary archive to Exchange 2007.You cannot offboard an Exchange Online archive mailbox which has auto-expanding enabled in Office 365.More info on the types of holds can be found here. This is because Exchange 2010 doesn’t know about in-place hold which was introduced in Exchange 2013 or about organization-wide holds in Office 365. You cannot offboard to Exchange 2010 an Exchange Online Mailbox that has any hold other than Litigation Hold.On-premises migration admin needs to have the minimum required permissions and valid credentials.Maximum number of items per regular mailbox folder is 1 million and 3 million for the dumpster, reference here.Even if you have auto-expanding enabled in Exchange Online, as of this writing the maximum mailbox size for migration of main archive is still 100GB – reference here. Make sure your migration users are synchronized with AADconnect tool and corresponding mail users are provisioned correctly on the Exchange Online side for corresponding on-premises mailboxes (ExchangeGuid present, alias, recipient type correct, accepted domains for the email addresses and secondary smtp address Maximum storage quota in Exchange Online for both primary and archive mailbox is 100GB each.Exchange Online requires Negotiate (NTLM) authentication for MRSProxy.MRSProxy needs to be enabled and running on Exchange on-premises.Sometimes, resuming of the move can help, especially if there were some temporary issues on the Exchange Online side that were addressed.īefore getting into troubleshooting, I recommend you check the following ‘Minimum Requirements’ those are the things we know will break migrations (and we see them do so):
The move is stopped and needs the administrator’s attention to investigate the reason of failure.
This blog post is a part of a 5 post series consisting of: