[jitsi-dev] Problem in file transfer

Hello sir iam facing a problem while transferring file through xmpp on
another server(not jit.si),iam using openfire,but after 2-3 seconds my file
automatically cancelled,please help me in resolving thanks,and the speed of
transferring is also limited to only 2.9 kbps,whereas in spark iam getting
above 15,how to increase speed of transferring file?