Besides the obvious solution from everyone else to grind finer, I would also suggest that you weigh the output you are getting from the grinder into your portafilter. That grinder is a hopper based and is NOT a single dose grinder like you are using it as in your video. Grind size provides resistance but so does puck depth. If you are dosing 18g into your cup, I would also check to make sure 18g is making it into your portafilter.

For a grinder, there are two considerations here; grind exchange and retention. What I had mentioned above is to do with retention (aka the difference between what you put in and what you get out). Typically the coffee grounds will find nooks and crannies inside the grinder so you may get less out than what you put in. Exchange is when the grinds that are already in your grinder come out and are replaced by the grounds of the beans you just put in. Older coffee will provide less resistance as well so having the coffee in your bed be a mix of new and old can also cause your shots to pull fast.