OSX 10.11 El Capitan install fails with "This item is temporarily unavailable."

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence.

Computer Qualify for the Monterey upgrade

macOS Big Sur 11 hardware requirements

macOS Catalina 10.15 hardware requirements

macOS Mojave 10.14 hardware requirements

macOS High Sierra 10.13 hardware requirements

macOS Sierra 10.12 hardware requirements

OS X El Capitan - Technical Specifications

If the drive is truly empty of any operating system

1 - Restart the computer in Recovery Mode ( Command + r ). This is going to required and active and working Internal Connection. Suggest connecting via Ethernet Cable to Router

2 - it this works - choose Reinstall macOS or OS X whichever is states

3 - refer to image below but it will not offer Monterey as it appear in image below

4 - It will download the version of OS X or macOS associated with the Recovery Partition on the computer

Two things here. You should boot into Recovery Mode using Command + Option + R which should eliminate the need for supplying an AppleID. Years ago I saw an Apple article which mentioned this detail for people preparing a Mac for resale.

Second, you are booting to an outdated version of the installer which has an expired certificate. You need to set the date to some time in 2017 (or perhaps even earlier if necessary). While booted to the installer, launch the Terminal app from the Utilities menu and use the following command to set the date & time to Jan. 2, 2017 @ 11:33am (adjust the year according if necessary):

date  -u  0102113317

If there are no errors, quit the Terminal app and select the "Reinstall macOS" option.

Sorry, should have read closely. I’m currently having the same issue and had the chance to speak with Apple and real reason is it’s no longer supported. I was also told that it now can be downloaded from its help page on getting old OS systems.

Yes, I already know that as the problem still remains the same.

I had El Cap OS already had to deeper back to snow leopard but it won’t upgrade to El Cap. The installer is ahead of its time v. 2 not the correct installer needed. Is this an error on Apple’s part?

hi im followed all you steps and it still give me that message that this item is temporarily unavailable try again later

Best Results are via Ethernet Cable to Router.

This will avoid any iff connection via Manual Inputing the Wifi password