I use the following command to return an Activation based floating license to Xilinx.
xlicsrvrmgr -returntransaction request=return.xml response=response.xml "proxy=\"10.60.70.90 0090 ]\""
However, xlicsrvrmgr then closes with the error message below:
This behavior has been observed on networks where there is a firewall blocking the "HTTP Upload" protocol.
This affects Xlicsrvrmgr.exe because the "returntransaction" command uploads some information back to Xilinx.
To work around this issue, copying the file which is created "return.xml" to another machine which has direct access to the internet and run the "returntransaction" command there.
Once the "response.xml" file is created, copy this file back to your license server and run the following command to remove the trusted storage.
xlicsrvrmgr -p response.xml