Multi Network issue : client controller

Im study Unreal engine4 (multi play)

My problem is server player create ssession and login Ok

but client window join ssession can’t move client spawn character(run on server)

um…but client window first create ssession and server window join ssession… everything OK

actually real launch game not problem but i want know why client first create only is working…

Sorry i’m sucks english level…

Please HELP