Hey guys im a little bit lost.
What happend to the input mapping in 4.23 ?
I see Speech mappings but the axis mapping is gone ? Am i stupid or what 
Hey SassiX,
Same Problem Here, I guess its a Bug :\
If you simply add these two lines to your Config/DefaultInput.ini and restart the Editor.
+ActionMappings=(ActionName="",bShift=False,bCtrl=False,bAlt=False,bCmd=False,Key=None)
+AxisMappings=(AxisName="",Scale=1.000000,Key=None)
The Options reappear inside of the Project Settings.
Don’t delete them right away inside the editor if the Array is empty the option is immediately removed again.
Good Luck 
4.23 is still in Preview, report the bug anyway so that the final release will get fixed.
Aye, thx for the response guys !
I have the same problem. Im working with Unreal Studio though as I need to use datasmith. I tried to add these two lines to the .ini files but nothing happens. Did it work for anyone?
Got the missing axis mappings when the config files were absent from the config folder. Creating a new project and copying over its config files (to the desired project’s config folder) fixes the issue. Got the idea for this form @RenéB’s previous post!
I did what Jonathan suggested, worked like a charm. Thanks!!! I appreciate the information, it saved me a great amount of time and frustration.