Summary: ActiveSync is the synchronization protocol of the Exchange Sever. If there are any issues with the ActiveSync, then the service would fail with the ActiveSync Health Set Failing error message. In this post, we will understand the possible reasons behind the error and provide solutions to fix it.
ActiveSync is an important protocol in the Exchange Server, which is responsible for synchronization that enables the devices, such as mobile devices, tablets, and others, to access the emails, calendar, contacts, and other resources on the server. It features real-time synchronization between devices and resources, manage push notifications to ensure immediate alert of new messages without any manual refresh, secure communications between the device and the server, enforcement of policies from the Exchange Server as well as remote-wipe of the device in case the device is stolen or lost.
The ActiveSync protocol is constantly being monitored by the Exchange Server Health Set Monitor. If the ActiveSync health set is unhealthy, then the administrator receives an alert from the said monitoring protocol saying that the ActiveSync Health Set Failing. This could prevent users and devices from accessing the mailboxes or getting push notifications. There could be many issues that may cause such an issue.
Possible Causes for the ActiveSync Health Set Failing Error
Here are some common reasons that can may lead to the ActiveSync Health Set Failing error.
- Network Issues
Configuration changes to block ports or any network changes can impact the functioning of the ActiveSync protocol. Such an issue may occur due to new configuration on the routers, edge firewalls, DNS changes, or introduction of new devices.
- Misconfiguration
Introducing new things or locking down the configuration can lead to misconfiguration of the Exchange Server and ActiveSync issues. Such configuration changes in the virtual directory settings or policy can lead to the health set errors.
- Performance of the Server
If the server is on a high load due to abnormal traffic/use or the server doesn’t have the recommended hardware specifications, like RAM, CPU, or hard drive, then this can lead to the server to underperform and may cause such issues.
- Software Updates or New Software
Software or operating system updates or introduction of new software and configurations on the server can lead to ActiveSync issues. This might happen if a software update contains a bug that might have affected the ActiveSync. Introducing new software could also lead to conflicts between the new software and the protocol.
- Database Corruption
Sudden loss of power, hardware failure, malware attacks, or human error can lead to database corruption or transaction log corruption. Although it will not directly impact the ActiveSync, it will affect the entire user experience.
Ways to Resolve ActiveSync Health Set Failing Error
Here are some possible ways to resolve the ActiveSync Health Set Failing Error.
Check the Event Viewer
The first thing you need to do is check the Event Viewer. This will help you to understand what is failing and where. It can be a very good source of information regarding the error and where it could lead you.
Retrace the Steps
The other thing to check is what has changed from when the server was working to when the issue was first identified. Ideally, when there is a change in the network/server/infrastructure, introduction of new software/hardware to the server or patching installed, there is a change management request for the maintenance done as well as all the changes are logged and documented. This will help in getting more information on what could have caused the issue, which will possibly allow you to reverse the changes done. When working with patching, you should always verify the patch and check any listed known issues with the patches. This will possibly help resolve issues related to the network, misconfiguration, and software updates or new software.
Re-run the Probe
The next thing is to check exactly the error message on the Health Monitor. For this, run the following command:
Get-ServerHealth <server name> | ?{$_.HealthSetName -eq "<health set name>"}The health set name can be retrieved from the Get-ServerHealth command (see the below example).
Get-ServerHealth srv01.company.lan | ?{$_.HealthSetName -eq "ActiveSync"}
After this is completed, you would have more information on the ActiveSync issue. If there is a problem with the ActiveSync, it will show as Unhealthy under AlertValue. To verify if the issue was a one-off, you can re-run the probe using the below command:
Invoke-MonitoringProbe <health set name>\<probe name> -Server <server name> | Format-List
Recycle the IIS Pools
Since the ActiveSync protocol is a web service, it sits on the IIS of the Exchange Server. So, you can reset the IIS using the below command from an administrative command prompt window.
iisreset /restart
If this doesn’t work, you can try to recycle the application pool of the virtual directory of the ActiveSync. For this,
- Open the IIS Manager.
- Expand the server and click on Application Pools.
- Right-click on MSExchangeSyncAppPool and click on Recycle.
- After this is done, confirm that the app is Running.
Perform Database Recovery
When a database or transaction log is corrupted, the database will not mount and the users or services will not be able to access any resources. In such a case, you can try to perform smooth recovery of the database using the ESEUtil command. But first you need to see the database state by using the below command.
ESEUTIL /MH "<database full path>"If the state of the database is Dirty Shutdown, this means that there is some kind of corruption in the database or logs. To run a smooth recovery, you can use the below command.
ESEUTIL /R "<database full path>"After the database repair is finished, you can check the database state again. If the state is Healthy Shutdown, then you can go ahead and mount the database and test the ActiveSync. If the state is still Dirty Shutdown, you can perform hard recovery by using the below command.
ESEUTIL /P "<database full path>"This will basically create a new copy of the database (make sure there is ample space). Depending on the database size and complexity of corruption, the process may take some time. Also, it will just purge anything which is deemed corrupted, resulting in data loss.
After hard recovery, defragmentation is needed. To do this, use the following command:
ESEUTIL /D "<database full path>"Alternative Solution to Recover Data from Corrupt Databases
Specialized Exchange recovery tools, like Stellar Repair for Exchange, can serve as an effective solution for recovering data from corrupted databases. This tool can seamlessly open Exchange Server database from any version and without size limit.
After a quick or deep scan, you will be presented with the entire structure of the database. You can granularly export the data to PST and other file formats. If the Exchange Server is running healthy, you can create a new database and directly export the data to the live database. You can also export the EDB data directly to Microsoft 365 account.
This tool helps reduce the time of recovery, requires less resources, and ensures complete recovery of the EDB file data. It can recover user mailboxes, shared mailboxes, user archives, public folders, disabled mailboxes, and even purged/deleted items.
