I have a clean installation of Openfire 4.1.5.
The Openfire instance is directly on the Internet (not proxy, not firewalls).
As a client on PCs I use Spark 2.7.7
And on android phones try using several XMPP clients.
The server has the File Transfer Proxy Configuration feature enable
Among Spark clients on the same network, I can transfer files.
Among Spark clients on different networks, I can transfer files.
Among Android customers testing several app. I can not transfer files.
Between Android and Spark customers, I can not transfer either.
Could you tell me which logs I need to check in order to get close to a solution?
Or how did you solve this problem?