Hello @Badr HOUSSNI ,
You can use NSG flow logs in Network Watcher to generate flow logs for any VM’s traffic, including that which traverses the Load Balancer resource. This is described here: https://learn.microsoft.com/en-us/azure/network-watcher/network-watcher-nsg-flow-logging-overview
Enable NSG logs : https://learn.microsoft.com/en-us/azure/network-watcher/network-watcher-nsg-flow-logging-portal
Kindly let us know if the above helps or you need further assistance on this issue.
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