Next, open the Dope Sheet and switch to the Action Editor. First, deselect all NLA strips on your armature from the Non-Linear Animation editor.

The 'frame_range' error is caused by trying to bake rootmotion on a NLA strip, instead of a raw Action. blend file which still has the constraints active. Then you can 'Append' the newly created actions later into your main.

To avoid this, be sure to do all your root motion conversion in a COPY of your main. If you are working with a dual rig system (control rig and a game rig as described in CG Dive's YouTube tutorials) keep in mind that Mixamo Rootbaker addon will clear your constraints, which is NOT desirable for this setup. (If you are NOT using a dual-rig system, you can ignore Prerequisite Step 2.) However, the older Mixamo converter by 'enziop' will still work fine up to Blender 3.0.1 only (01-26-2022 release). First, if you are using Blender 3.1 - 3.3 or newer, make sure you are using the NEW fork of Mixamo Converter by 'brkeejp' on Github ( available here), otherwise the addon will give you a different error message: 'NLA_OT_ame_start expected an int type, not float'.

Mixamo blender addon