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When there is a slow performance of obtaining network licenses over VPN or when the network licenses cannot be obtained at all, it may help to adjust the firewall and VPN settings to "Enable fragmented traffic. Please see the Slow performance of RMS over VPN entry in Sentinel FAQ for additional information.
For troubleshooting purposes, you may also want to check out the license via WCommute.exe to confirm that the issue is indeed related to retrieving the license over the network.