This article explains how the sync invoice history options works
When setting up Cloud Depot for the first time, it is essential to define a sync history that aligns with your needs. You may begin with a shorter sync history period to prevent the import of unnecessary historical invoices.
However, once your sync is established and functioning smoothly, it is advisable to extend the sync history to at least 30 days. This extension is vital, as it allows the system to backfill and retrieve any missing invoices in the event of disruptions to your sync, such as disconnections from Xero or issues with Autotask credentials.
If a disruption occurs and your sync history is set to a shorter duration, there is a risk that the sync may not capture any missing invoices. To mitigate this issue, it is recommended to extend the sync history to at least 30 days.
To change the setting in Cloud Depot
Autotask to Xero -> Configuration -> Xero Options