Jetpack Mobile Theme not working!

I’ve been using Jetpack for mobile theme support since I migrated from Blogger to WordPress. From last few weeks, I’m facing a trouble regarding the mobile theme. I have WP Super Cache for caching and Jetpack mobile theme was working fine with it earlier. But it ain’t working fine now. Whenever I access my website through my phone, I get the full layout, instead of the simplified mobile version. Sometimes it works fine and sometimes it don’t. It’s a fairly heavy theme with lots of images, so it can take a while to load the website depending on the person’s internet connection, and I’d really like to have the mobile theme back to functioning. Is there anything I could do to solve this issue?

Here is my site: https://mashinie.com