Backup email M365 problem

[kikanq]

Hi,

I am backing up Exchange M365 mailboxes for the first time.

I have created dynamic groups in EntraID for my tenant – I have 8 groups, each with about 100 users.
Each group is a separate backup task in my VBO365 console.

So I have 8 tasks to back up my employees' email boxes.
Each of these tasks will ultimately be handled by this proxy server: Windows Server 2022 (4CPU, 32GB RAM).
The proxy server has an iSCSI repository connected (the repository is a Synology NAS server).

For example, I run ONLY ONE TASK:
During the task, several mailboxes will perform their backup, but many of them have errors such as:

:: Processing archive mailbox test@myorganization.com failed with error:
An error occurred while sending the request.. An error occurred while sending the request..
Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host...
An existing connection was forcibly closed by the remote host.

or

:: Processing mailbox test@myorganization.com failed with error:
A connection attempt failed because the connected party did not properly respond after a period of time,
or established connection failed because connected host has failed to respond. (outlook.office365.com:443).
A connection attempt failed because the connected party did not properly respond after a period of time,
or established connection failed because connected host has failed to respond. (outlook.office365.com:443).
A connection attempt failed because the connected party did not properly respond after a period of time,
or established connection failed because connected host has failed to respond.

Please help me. What should I do in this situation? How can I fix this?

[aeph]

Let them run into a retry.

If this is the initial backup, it may happen that the first few runs return a corresponding message. These connection problems usually resolve themselves during the retries. Give the job time.

[karsten123]

disable exo throttling for initial backup

[kikanq]

disable exo throttling for initial backup

If you're talking about this: https://www.veeam.com/kb4198

I did it before running the first backup

[Mildur]

Hello Kikanq,

Please open a support case — the forum isn’t intended as an alternative to technical support as explained in red letters when creating a new topic.
Could you please share the support case ID for this issue? Without a case number, the topic will eventually be deleted by moderators.

Thank you for understanding,
Fabian