first you have to get access to PAYDAY 3 BETA.

then after downloading, enter the game

start the matchmaking and use your mask. After all of this, press SPACE button. (usually that button is in your keyboard)





and there you go! you succesfully jumped.

but if you see this issue, then try change your account and run the game again.
i dunno but it worked for me.



Also there can be another type of problems that may not let you just jump.
in that case tap on ESC button (usually on top left corner of your keyboard) and go to the settings. there you can obviously see the KEYBOARD section (example picture below)



hope you can finally jump! xd