Why won't this redstone and command block setup work like the other one?

I'm trying to make an RPG adventure where the player can interact with different stuff. For example, if he walks up to a crafting table, then this text should come up in chat:
[Robert:] I wish there was a Crafting Guide in Minecraft or something, it's always so hard to remember what some of the crafting recipes are!
The crafting table works fine, I have a hopper clock connected to a redstone which has a repeater going into a command blocks saying:
/testfor @a[6,80,3,1]
Connected to a comparator connected to a command block saying
/tellraw @p ["",{"text":"[Robert:] ","color":"dark_blue"},{"text":"I wish they had a crafting guide in Minecraft or something, it's always so hard to remember what some of the crafting recipies are!","color":"white"}]
This works fine. When I walk up to the crafting table, it works. But when I walk up to the ladder, well that's a different story.
In my "Ladder Interaction" section of the redstone, I have the same hopper clock, with the same item, connecting to the comparator in the same way, with the redstone to the repeater, connected to this command block:
/testfor @a[-20,84,7,3]
Connected to a comparator which is then connected to:
/tellraw @p ["",{"text":"[Robert:] ","color":"dark_blue"},{"text":"Uh-Oh! The lava must've burned some of the ladders, so I need another ladder in order to get up. Come on! Better find one quickly!","color":"white"}]
I don't understand why this one won't work but the other does. I changed my redstone clock to a hopper clock, like I said, because people said that it keeps the chunks loaded and stuff, but it still doesn't work.
Here's a picture of my design:
Can you help me?
Best Answer
There is this one character (I don't know what it is yet, either), that sometimes, somehow, makes its way into commands. Try going to the beginning of your /testfor command, and holding -> until you reach the end. There may be a spot where your cursor stops moving, and there should be a zero-width invisible character there. It shows up in regular editing software, I always check if my commands aren't working.
Pictures about "Why won't this redstone and command block setup work like the other one?"



Do command blocks work with Redstone?
Command blocks are a specialized type of block within a Minecraft: Bedrock Edition world that allows the use of console commands in-game. The same commands that players can type from chat can be run automatically by command blocks using redstone power.How do you activate a command block with Redstone?
To activate the command block, just activate the redstone device that is attached to the command block. In this example, the redstone device is a lever. So you would activate the command block by toggling the lever.Why is my command block not working in Minecraft?
Enable Command Blocks Head to your multicraft control panel and select the Config Files tab on the left hand side. Select Server Settings which will be at the top of the page. Scroll down the page until you find Enable Command Blocks. Set this setting to Enabled and then click save.How do two command blocks work at the same time?
To make your command block run multiple commands, you will need to summon FallingSand or falling_block (depending on your version of Minecraft) with command blocks and redstone blocks for each command. The command blocks will be stacked one on top of the other and contain the individual command.LICD: Why Won't She Leave
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Tranmautritam, picjumbo.com, Pixabay, Roberto Nickson