Yes, this is a mixed content issue. In addition to what @sdayman suggested you could try enabling Automatic HTTPS Rewrites on the Cloudflare dashboard > SSL/TLS app.
If you have a caching plugin for your site, clear that cache.
I also suggest you go to the Cloudflare Caching tab and Purge the cache of All Files.
If you have Shell access on your web server, and are lucky enough to have WP-CLI installed, you can run: wp search-replace http://webshopmechanic https://webshopmechanic
That will update any URLs you missed. I left off the .com for simplicity, as it’s really the first part that needs to be fixed. The search-replace command will accurately replace exactly what you specify.
p.s. I see you’re running Jetpack. I’ve not used that, so I suspect there’s a bit more work to do. It looks like Jetpack is providing some CDN, which should also be cleared.
Some of the images I mentioned have been fixed. There is one holding you up, it’s the background image of your contact form - the one with
I assume this is part of the wordpress plugin you’re using for this form. I’m not sure if it’s Yoast SEO (I can see that you’re using that plugin), or another plugin that you have installed. There may be settings in that plugin where you can update the image URL.
I’m not familiar with Yoast SEO, but this article states it uses canonical URLs. If it is indeed managing your contact form there should be a way to update the URL from the Yoast settings - bug again, I have not used that plugin.