Client error: Can't find free port - Error: Timed out requesting agent port for client sessions.

These errors may occur because either:

• A firewall prevents the remote machine from initiating communication on one or more of the assigned transmission channel ports, causing the process to increment the port it attempted to use until it exhausted the list of ports it was given.
  
  or
• A Managed Server (Windows or Linux) has had its default configuration altered so that the range of ports it would use is insuffucient, causing the process that is trying to start not to be able to find an available port to use.
  
  Here is an extreme example where the Managed Server has been configured only to allow two ports to be used:
  
  
  
  

Check Firewalls

Review the firewalls present in the environment to ensure accommodations have been made for the ports used by Veeam Backup & Replication.

Check Managed Server Configuration

The default range of transmission channel ports is available in the Used Ports section of the user guide.

1. Within the Veeam console, click Backup Infrastructure
2. From the tree on the left, expand ‘Managed servers’ and select ‘Microsoft Windows’
3. On the right side, select the server related to the issue
4. In the menu at the top of the screen, click Edit Server
5. On the ‘Credentials’ tab, click the button labeled [Ports…]
6. Within the network settings dialog, verify that either the default or an appropriate number of ports have been assigned.
   
7. Click OK to confirm the settings.
   
8. Click Finish to commit the changes to that server.