How to render UI in background?

I tried achive simple target – character move to some point and then engine render ui.
For this task I created background task, pass character movement component and check components status.
But, after this editor crushed with message “Slate can only be accessed from the GameThread or the SlateLoadingThread”.
How to I should do this properly?

Tryed this one.

AsyncTask(ENamedThreads::GameThread, =]() { menu->AddToViewport(); });

Still have same error.
Please help.