Impossible to download MacOs Mojave

Hi everyone.

I tried to install Catalina, but it made the computer impossible to shut down without errors and fails.

I tried to download and come back to Mojave, but the link to the App Store resulted in "impossible to access to the App Store" (while being into the App Store) or "impossible to find this item".

I thought that maybe, since Catalina is the last release, it doesn't permit you to get older versions, so I looked for and found an installer for MacOs El Capitan (the same this computer came with).

I installed but even from this store I can't upgrade to Mojave.

Maybe is because I bougth this computer in italy and now I live in spain.

The following is the page that sends to the App Store:

And this is what I see then:

The search bar is useless too. "mac os mojave" or "mac os 10.14" return no os.

Where can I find a Mojave installer?