Macbook Pro 2015 won't recognize iPhone 12 Pro any longer

I have a 2015 MacBook Pro running El Capitan (10.11.6) and an iPhone 12 Pro running 17.2.1. When I plugged my phone into my MacBook today I received the note on my MacBook that a software update is required to connect to my iphone. I click "Install" and it appears to be "downloading 1 item". Then I get this error "Installation failed. Can't install the software because it is not currently available from the Software Update server." I have restarted my macbook and my iphone. I also went to "updates" in the app store on my MacBook and there's nothing there. I also followed the instructions below (which I found in this forum from last year) to find the folder for the update and it says there is no update available. Help?

Tried this too - no luck:

For iOS 14 or later you need iTunes 12.8.2.3 or better running on OS X 10.11.6 or better. See How to upgrade to OS X El Capitan - Apple Support if required.

Assuming a suitable version of iTunes is in place then in Finder use the menu item Go > Go to Folder..., copy the following text, paste it into the dialog box and press enter:

/System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources

Unlock your device and connect it to USB. Double click on MobileDeviceUpdater in the folder that has opened. It should notify you of a software update. Install it and iTunes should hopefully recognize your device.

If these steps haven't worked you can also try reinstalling iTunes12.8.2.3.dmg (El Capitan/Sierra) or iTunes12.8.3.1 (High Sierra) while your device is connected and unlocked.