I solved this, I had to reset script
Video :
I need answer to this as well, is this a bug in engine not fixed , and I’m using latest engine, downloaded yesterday.
I looked everywhere, no answers anywhere on this question and I looked in many places, ending without a fix so coming here, and not being able to SEE what author of video above does, given its off screen. Any ideas ?
Hello–
What is the error you are having?
SO sorry, I tried to come here earlier to say its ok now, but I couldn’t find the thread under conversations but I finally did.
It’s been a long but fruitful day following John Lemon 
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What was your solution? I’m having trouble too
This is why I did no like working with unity they never fix any bugs just wanted so bad to learn this engine looks like will have to go back to unreal engine
That’s because it’s not a bug.
It’s actually a fat-finger typo by OP.
Look closely at the image.
The OP was using Reload; as his input axis name.
Over in the InputManager setup field the actual text is Reload
Those are NOT the same string, so of course it doesn’t work.
If you’re actually interested in fixing your script, make sure you type accurately.
If you arrived here by monkey-hammer-banging tutorial code in, this will save you a LOT of time:
How to do tutorials properly:
Tutorials are a GREAT idea. Tutorials should be used this way:
Step 1. Follow the tutorial and do every single step of the tutorial 100% precisely the way it is shown. Even the slightest deviation (even a single character!) generally ends in disaster. That’s how software engineering works. Every single letter must be spelled, capitalized, punctuated and spaced (or not spaced) properly. Fortunately this is the easiest part to get right.
Be a robot. Don’t make any mistakes. BE PERFECT IN EVERYTHING YOU DO HERE.
If you get any errors, learn how to read the error code and fix it. Google is your friend here. Do NOT continue until you fix the error. The error will probably be somewhere near the parenthesis numbers (line and character position) in the file. It is almost CERTAINLY your typo causing the error, so look again and fix it.
Step 2. Go back and work through every part of the tutorial again, and this time explain it to your doggie. See how I am doing that in my avatar picture? If you have no dog, explain it to your house plant. If you are unable to explain any part of it, STOP. DO NOT PROCEED. Now go learn how that part works. Read the documentation on the functions involved. Go back to the tutorial and try to figure out WHY they did that. This is the part that takes a LOT of time when you are new. It might take days or weeks to work through a single 5-minute tutorial. Stick with it. You will learn.
Step 2 is the part everybody seems to miss. Without Step 2 you are simply a code-typing monkey and outside of the specific tutorial you did, you will be completely lost.
Of course, all this presupposes no errors in the tutorial. For certain tutorial makers (like Unity, Brackeys, Imphenzia, Sebastian Lague) this is usually the case. For some other less-well-known content creators, this is less true. Read the comments on the video: did anyone have issues like you did? If there’s an error, you will NEVER be the first guy to find it.
Beyond that, Step 3, 4, 5 and 6 become easy because you already understand!