Posted on 03-22-2016 01:50 PM
Today we suddenly lost the ability to log into the App Store using our Apple ID on new hardware running OS X 10.11.3. We later determined that this was the case whether we imaged first or not.
It worked fine yesterday, prior to the release of 10.11.4.
Downloading and installing the the 10.11.4 Combo Update manually fixed the problem.
Posted on 03-22-2016 02:14 PM
Wow! Thanks for posting! I've been fighting this issue for the last two weeks, thinking it was our network restrictions! Looks like 10.11.4 may have helped here too!