MacOS X Lion won’t download

How are you downloading Lion? Are you using the download link from the Apple article @Limnos linked, or are you downloading Lion through local recovery mode, or Internet Recovery Mode?

What is the exact model of the Mac and its current version of macOS? You can get this information if the Mac boots into macOS by clicking the Apple menu and selecting "About This Mac", or if the Mac cannot boot into macOS, then enter the system serial number here:

Check Your Service and Support Coverage - Apple Support

You won't be able to download Lion to a Mac that shipped with a later version of macOS.

Click on this link to read how to get different versions of macOS --> How to download and install macOS - Apple Support

Doyou havea good Internet connection, preferably Etherrnet?

Refer to this document for ways to contact Apple ➞ Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone ➞ Contact Apple for support and service - Apple Support

What is the exact model of your Mac? Use the "Check Coverage" link in my previous post in order to identify the exact model of your Mac. Without knowing the exact model, it makes it difficult for us to assist you to provide all the options available to you.

Plus, has macOS 10.12.6+ ever been installed on this Mac at any time in the past? This is very important to know whether you have access to Internet Recovery Mode or just local recovery mode.