Low Message Size Limits
The Exchange server we are attempting to migrate to timed out during the migration of an item. This is usually caused by size limits on the server smaller than the size of the item we are attempting to migrate. For example, the size limit of the server is 10MB but the item has a 20MB attachment.
By default, Exchange Server has message size limits of 10MB. For more information about message size limits on Exchange Server:
You can verify if you have exceeded the server size limits by:
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- Sign in to your MigrationWiz account
- Click on Perform Mailbox Migration.
- Select the Mailbox Project you are receiving the error on, and click on View Mailboxes.
- Select the Mailbox with the corresponding error, and click View Statistics.
If the average error size is greater than 10MB, it is likely that you have hit message size limits imposed by Exchange Server.
Over-utilized Resources
An overloaded Exchange server may cause responses to be slower than what the underlying network expected. Also, high network utilization will result in slower-than-expected responses, since the amount of bandwidth needed to fulfill the requests exceeds the amount of bandwidth available.
Resolution:
Low Message Size Limits
See Increase the message size limits on the Exchange Server.
Over-utilized Resources
If you have validated that your credentials are working properly, it is possible that you may have over-utilized resources.
First, attempt to open your OWA URL from an external network from a system that is not joined to your domain. If OWA is loaded in a timely manner, check your server resources:
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- Check server CPU usage;
- Check memory usage;
- Check disk I/O usage using performance monitor; and
- Check for over-utilization of network.
The most common problem encountered is the over-utilization of network. This means that you are attempting to migrate too many mailboxes simultaneously, and do not have enough bandwidth to execute them. Refer to Introduction: Throttling Bandwidth. Once you have a better understanding of network utilization, configure the correct number of mailboxes you can migrate simultaneously.
Get the subjects of failed items and retry
Once the mailbox migration completes: