What is a 3014 error code when trying to restore ipad?

Perhaps you actually refer to error 4013?

See >>> If you see error 9, 4005, 4013 or 4014 when you restore your iPhone, iPad or iPod touch – Apple Support

The exact verbiage was a dialog that said “The iPad “iPad” could not be updated. An unknown error occurred (3014).”

I was able to resolve this only by using a different MacBook Pro to perform the restore.

I got this as well. I tired other USB ports. That eventually worked.

Error 3014 is very non-specific. This resource is the only reference that I can locate relating to this error:

If you see Error 3194, Error 17, or 'This device isn't eligible for the requested build' on your computer - Apple Support

I got 3014 as well so I suspect the OP got it correct.

After tethering to computer (MacBook Pro on 12.3.1) got 4000 error trying to upgrade to latest 15.4.1. Multiple attempts indicate need to restore according to dialog.

This 3014 error after many attempts to update to 15.4.1.

Failed verification, I can never update over my Wi-Fi, always have to tether to computer it seems.

Tried updating on multiple devices and it is taking days. Very frustrating to say the least and I’m in the IT field and have some patience for tech.

It’s good to learn that you’ve resolved the problem.

Thanks for input MrWaVeS, I will try that next update if I run into same issues.