"Aiming" can not be assigned to the "Space" key

When I place the “aiming” function on the Space button from the second mouse button, there is only an incomplete animation of the aiming. The animation trembles because it breaks off constantly and restarts.
Platform: Windows 10

Steps To Reproduce:

Images / Videos:

Host or Client: Host

Players in your game: 1-4

Specifications:
Intel 6700k, Geforce Gtx 1070