You have an interesting LCD1602 which appears to have alternative rows for the pin headers. Can you post a link to the supplier's product page ?
Since you appear to have the Backligh LED, contrast and power pins correct I guess that it is a wiring error but check very carefully, if there is labeling on the LCD pins, that the labels match those in the tutorial.
Edit:
I found the display Basic 16x2 Character LCD - RGB Backlight 5V - LCD-10862 - SparkFun Electronics
You did notice the two additional pins on it which do not appear in your tutorial ? It does looks like you have counted from the right and got at least at least the connections DB4 to DB7 wrong.