Unable to access the Nether

There is a bug where I cannot access the Nether. I stand there and it doesn't teleport me.

Steps to Reproduce:

1. [Step 1]
2. [Step 2] Sorry I have no idea what this means..
3. [Step 3]

Observed Results:
I stand at the portal and nothing happens, I just hear the sounds and see the purple particles flying around.

Expected Results:
I want to go through to the Nether but I can't.

Screenshots/Videos attached: Video has been attached.

Note:

Add-Ons I currently have on are:

Warpstones by Mythicus Studios

World Utilities Add-On by Gamefam

The Uncrafter RP by Ninja Squirrel Gaming

Gravestone Add-On by Darkosto

XP Crystal Bank Add-On by Scai Quest

Stuff It Add-On by Big Dye Gaming

Backpacks Add-On by Scai Quest