macOS High Sierra on the App Store: the Learn More button doesn't work App Store &gt; macOS High Sierra &gt; Download

We could not complete your purchase.
You do not have enough space to install macOS High Sierra.
[ Learn More ]  [ OK ]

That [ Learn More ] button does nothing at all. I opened the Console app and filtered the messages using &quot;App Store&quot; and I found this:

Rejected request to open untrusted URL DABuyButtonLearnMoreURL.Yosemite

I'm running macOS Sierra 10.12.6
I had the same issue and I thought I had enough space but I didn't. You need at least 14.3GB I believe. It downloaded for me afterwards