Common Issues

This section describes issues which are seen in the field more often, possible reasons and mitigations.

Slow backups due to high sync times
Hybrid Auth WSMAN-MultipleClientMessages (Certificate issue)
HTTP proxy config

Slow backups due to high sync times

When encountering very slow incremental backups even on low or no changes in M365 items (e.g. a mailbox), check for min/max/avg sync times of items in the logs. Navigate to the VB365 log folder C:\ProgramData\Veeam\Backup365\<ORGANIZATION>\<JOB NAME> and run the following PowerShell command to search in the logs for sync times which are over 1 second.

select-string "Sync time: [^0]" *

This is an example output:

PS C:\ProgramData\Veeam\Backup365\Logs\<ORGANIZATION>\<JOBNAME>> select-string "Sync time: [^0]" *
...
Job.<JOB NAME>_2022_04_14_08_59_59.log:2732:[14.04.2022 09:00:08]   59 (8132)  Sync time: 143.7938527
Job.<JOB NAME>_2022_04_14_08_59_59.log:2737:[14.04.2022 09:00:08]   49 (4600)  Sync time: 324.8092703
...

Usually sync times are way below one second but of course there can be a few exceptions. However, if you get a lot of results from above query with values far greater than 1 seconds, you should double check your environment, e.g. if you’re not using a direct connection for your proxies. In case of doubt, open a support ticket with Veeam for assistance.

Hybrid Auth WSMAN-MultipleClientMessages (Certificate issue)

When adding a hybrid organization you get the following error when validating the organization in the wiyard:

WSMan-MultipleClientMessages - The WS-Management service cannot process the request

This is an issue with certificate authentication and can be either solved by disabling legacy protocols or by configuring on the Exchange server IIS > Default Web Site > PowerShell > SSL > and select "Client certificate: "Ignore" radio button

HTTP proxy config

You might need to configure a HTTP proxy to be able to connect to the internet but also have the requirement to define a bypass configuration list. This can be done by adding the list to xml config files on the Veeam Backup for Microsoft 365 Server and Proxies. Here is an example that bypasses *.lan.domainA.xy, *.external.com and 10.* :

<InternetProxy BypassHosts=".+\.lan\.domainA\.xy;.+\.external\.com;10\..+" />

For details on how to setup the bypass list, please see KB4174.