How to collect ActiveSync device logs to troubleshoot sync issues between mobile devices and Exchange Online
This article describes how to collect Exchange ActiveSync device logs to troubleshoot sync issues between mobile devices and Exchange Online in Microsoft 365. If you can't sync your mobile device to your mailbox, you may be asked by Microsoft 365 Support to collect logs for troubleshooting.
To capture ActiveSync device log information, follow these steps:
Run the Set-CASMailbox cmdlet to enable ActiveSync logging for a specific user:
Exchange ActiveSync debug logging is enabled for 48 hours in Exchange Online, and 72 hours in Exchange Server. After the time period expires, the value reverts to
Set-CASMailbox email@example.com -ActiveSyncDebugLogging $true
This example enables Exchange ActiveSync debug logging for the user firstname.lastname@example.org.
Reproduce the behavior that you want to capture.
Run the Get-MobileDeviceStatistics cmdlet to retrieve the log:
Get-MobileDeviceStatistics -Mailbox TonySmith -GetMailboxLog -NotificationEmailAddresses "email@example.com"
This example retrieves the statistics for the mobile phone configured to synchronize with the mailbox that belongs to the user Tony Smith. It also outputs the log file and sends it to the System Administrator at firstname.lastname@example.org.
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