How do I download Mojave for my older Mac from a Mac running Big Sur?

How old is the Mac that you wish to download the file on?

You can't install a version of macOS on a Mac that is older than the version of macOS that the Mac came with when new. So the system won't allow you to download it.

When I click View in Mac App Store on this page, https://apps.apple.com/us/app/macos-mojave/id1398502828?mt=12 the Mac App Store opens, but won't let me download the file because my Mac is only a year old, too new for Mojave.

Why can't you download the installer on the older Mac?

M1 Mac mini, macOS 12.1; Watch, series 5 GPS/cellular, watchOS 8.3; iPad Pro 2nd Gen, iPadOS 15.2; iPad Air 2, iPadOS 15.2; iPhone 12 Pro, iOS 15.2; TV 4th Gen, tvOS 15.2; HomePods, audioOS 15.2 and Airport Express w/ Airplay 2

This is so annoying. I need to download the Mojave installer in order to make a boot disc to recover an old Mac Mini. The Mac Mini isn't starting up, so I can't download the installer from there. But I also can't download it on my MacBook Pro 2020, because the app store won't allow it (Catalina). It won't download through Recovery on the Mac Mini either. So I'm pretty much stuck being completely unable to recover the Mac Mini. Please just let people download the installer!

I am on Monterey v12.2 via a MacBook Pro (16-inch, 2019).

I am able to download Monterey, Big Sur, and Catalina. I am unable to download Mojave and High Sierra. I get “Update not found” “The requested version of macOS is not available”. I presumed this was a CDN issue and came here to report it. But after seeing this; is my OS/HW configuration the cause? I'm not looking to install Mojave or High Sierra on this HW; I just capture the images for support/development purposes.

Take your ext disk to an Apple Genius Bar or an Apple Authorized Repair Shop and see if they can help you.