Nothing caching since adding SSL

I have no idea why but supercache just isn’t caching any pages for me. I’m using the basic (recommended) settings and have tried testing out multiple pages/posts but nothing will cache (the cache contents for both wp-cache and wp-supercache remain at 0).

Could this have something to do with having SSL on the site? I’m using Really Simple SSL plugin. When I originally set up the site (prior to adding SSL) I tested the cache and it was working. After adding SSL I didn’t check the cache, but now a month later I just randomly checked and it isn’t working. Having trouble narrowing down what the problem might be.

Any help would be greatly appreciated!

Some info on my site:

Avada Theme: 5.1.6

Server Info: Apache
PHP Version: 5.6.29.
PHP Post Max Size: 256 MB
PHP Time Limit: 10000
PHP Max Input Vars: 8000
SUHOSIN Installed: –
ZipArchive: ✔
MySQL Version: 5.6.34
Max Upload Size: 256 MB
DOMDocument: ✔
WP Remote Get: ✔
WP Remote Post: ✔
GD Library: bundled (2.1.0 compatible)

### Active Plugins (14) ###

Akismet Anti-Spam: by Automattic – 3.3.2
All In One SEO Pack: by Michael Torbert – 2.3.12.5
Autoptimize: by Frank Goossens (futtta) – 2.1.0
Fusion Builder: by ThemeFusion – 1.1.6
Fusion Core: by ThemeFusion – 3.1.6
Google Analytics for WordPress by MonsterInsights: by MonsterInsights – 6.1.10
Google XML Sitemaps: by Arne Brachhold – 4.0.8
Head, Footer and Post Injections: by Stefano Lissa – 3.0.7
Really Simple SSL: by Rogier Lankhorst – 2.5.16
TinyMCE Advanced: by Andrew Ozz – 4.5.6
Woocommerce Alphbetical Search: by Magnigenie – 1.1
WooCommerce: by Automattic – 3.0.7
WooZone – WooCommerce Amazon Affiliates: by AA-Team – 9.0.4.5
WP Super Cache: by Automattic – 1.4.9