Previewing bot on Facebook Messenger stops working a few nodes in

My bot runs fine if I am simulating it in your program, but whenever I try to preview it through Facebook Messenger either on my phone, or through Messenger on the Facebook web page, it stops a portion of the way through Episode 1 - it stops between the 9th and 10th nodes in my story

My use case:

I set a variable on an input node - 9th node:

What... is your favorite color?

{Color}

The user types in their favorite color (i.e.: Blue)

It is supposed to display this next, but it doesn't - it just stops:

Message Node - 10th node:

{Color}, really? I would have thought mauve, periwinkle, or even malachite... but {Color} - to each their own.

After the user has entered in their answer, nothing happens. The bot hangs. It doesn't say that the story ended, it just doesn't go to the 10th node.

Is there some sort of limitation when previewing it via phone or messenger (web)?

Can I not have a variable being called as the first line of text?

Is there something else that I am missing?

Thanks