Is it because I have a subscription version of Lightroom as opposed to owning Lightroom?

No. This is not the reason. The Juicebox Plugin for Lightroom will work find on subscription versions of Lightroom Classic CC.

What version of Lightroom do you have? Do you have Lightroom CC or Lightroom Classic CC (and what version number)? (You can check by going to 'Help -> About Lightroom...' from the drop-down menu at the top of the program.

You'll need Adobe Lightroom 4, 5 or 6 or Lightroom Classic CC 7 or higher.
Lightroom CC (not Classic) 7 and higher does not support plugins or web engines.

If you have a compatible version of Lightroom but still experience difficulties, then please let me know what operating system you have (Mac vs PC) and how far into the installation process you get (and what, if any, error messages you encounter along the way).
Thank you.

Thank you so much for all of this information. Unfortunately, none of this has worked for me. Is it because I have a subscription version of Lightroom as opposed to owning Lightroom? Please advise.

All the best,
Gabe

You'll find the Juicebox-Pro Plugin For Lightroom inside the Juicebox-Pro zip file in this location: juicebox_pro_1.5.1/adobe-lightroom-plugin/juicebox_pro.lrwebengine

Instructions for installing the plugin can be found on the plugin's own support page here.
First of all, extract the Juicebox-Pro zip file to your hard drive and then...
Mac: Double-click the juicebox_pro.lrwebengine package.
Windows: Drag-and-drop the juicebox_pro.lrwebengine folder onto your Lightroom desktop icon.

If this fails, then you can install the plugin manually by copying the juicebox_pro.lrwebengine folder/package to your Lightroom 'Web Galleries' folder.
Mac: Users/username/Library/Application Support/Adobe/Lightroom/Web Galleries/
Windows: C:\Users\username\AppData\Roaming\Adobe\Lightroom\Web Galleries\

I hope this helps.
If you get stuck with anything, please let me know and I'll try to help further.
Thank you.

Note regarding Lightroom CC vs Lightroom Classic CC:
In late 2017, Adobe split what was then known simply as Lightroom CC into two separate products.
Lightroom CC became Lightroom Classic CC and Adobe released a new version of Lightroom under the name Lightroom CC.
Unfortunately, the new Lightroom CC does not accept third-party plugins or web engines so it is not possible to use the Juicebox-Pro Plugin for Lightroom with this version.
You would need to have Lightroom Classic CC in order to use the Juicebox-Pro Lightroom Plugin (or any other plugin).

All the best,
Gabe

gabe.galdamez@gmail.com