OssSteam Both server and client get black screen after server travel

I’m in making 2Dbiew 1on1 strategic game.
This issue is began in test of packaged exe with my friend.

In standarone from editor, when window of server is active in desktop, only server get black.

Widget and network are running.

I think my issue is near by this.

But my English power and Scripter level is very poor…
Please somebody help me…

Maybe I reached near my answer.

I use “set view target with blend” (new view target is CameraAactor from persistent level) in beginPlay of levelBlueprint.

Keyboard input before ↑ node made correct view in screen.

but next issue is there, and I try more from now…