Numerical value greyed out for keyframes in time remapping

[Ella5E1A]

I'm trying to create a time ramp on this clip and Premiere has greyed out the numerical value for time remapping so I can't change the values at keyframes. I am wondering how to fix this? I've tried time remapping on the timeline and it just doesn't let me use it.  

[Ann Bens]

Keyframing is done on the timeline.

https://helpx.adobe.com/nl/premiere-pro/using/duration-speed.html

[Ella5E1A]

It doesn't even let me edit speed in the timeline. When I hit show clipe keyframes > time remapping > speed, the clip doesn't turn blue and I can't add keyframes.