File transfer in openfire 4.1.1 with spark 2.8.2

Good afternoon. Could someone help me I can not transfer files by the spark on port 7777, as I should proceed so that it works on the spark client.

In the local network we were able to transfer files but in the network wan we could not give error.
We already made nat on port 7777 but it does not work.
I need to help urgently !!!