Microsoft 365 API limitations on 01/03/2026 and Veeam backup applications

February 26, 2026 (Last Modified: February 26, 2026)

Microsoft 365 API limitations on 01/03/2026 and Veeam backup applications

This is a quick reminder especially for those using Veeam Backup for Microsoft 365 (the “non-cloud” version, the original one that backs up the M365 tenant to an on-prem repository, for example).

The new API usage limits introduced to reduce the number of concurrent connections can impact backup performance for customers running multiple Backup Applications. You can easily check how many are configured directly from the GUI.

The recommendation is to keep only one Backup Application configured, as explained in more detail in KB 4821.

We expect updates from Veeam to further optimize the application algorithms in line with the new Microsoft 365 throttling policies.

For those using Veeam Data Cloud for Microsoft 365, no action is required, as any necessary adjustments will be handled by Veeam on the server side.