This article provides a URL link to a download of El Capitan on the App Store, and the link is not working on my 2011 iMac running Yosemite 10.10.3 (on an intel i5 processor).
THis is the link: Connecting to the Mac App Store
iMac, OS X Yosemite (10.10.3)
That's right, because your Mac is incompatible. The article states:
If your Mac doesn't support High Sierra, or you're using Snow Leopard or Lion and would like to upgrade to High Sierra, follow these steps
Since your Mac does support High Sierra, it's not eligible to get El Capitan anymore.
You may be able to downgrade to Lion, and then upgrade to El Capitan.
That link won't work on a late 2009 or newer Mac running 10.8.5 or above; these can be upgraded directly to High Sierra. If you specifically need El Capitan, go to a Mac which is able to use the link, start downloading it, log into the Mac App Store with the same Apple ID, and click on the Purchases tab.
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unable to download El Cap from App Store
