Mojave will no longer allow signing into iTunes
iMacPro (2017) running macOS Mojave 10.14.6 will no longer allow signing into iTunes. iTunes is working on iPhoneX, iPod, Apple TV (4K) and iPad Pro. Just don't understand why all of a sudden I cannot access iTunes on a system that has worked for a couple of years with no issue.
[Re-Titled by Moderator]