I was trying to sign in to my Apple Account (iCloud+) on a MacBook Air running macOS 27 (GoldenGate), but nothing happened—I would enter my email and password, and then... nothing.
On the `account.apple.com` website, it worked fine using my primary email address.
On `icloud.com`, however, it didn't work with my primary email, but it *did* work with another email address associated with the account. This was a clue: the issue likely stemmed from the primary email address itself.
Attempting to change the primary email address via the website required entering the Apple Account password for that primary email, but it consistently returned an error ("invalid password").
I tried every solution suggested in the community, but none worked.
At one point, after booting into Safe Mode and creating a new administrator account to test the login, the following message appeared:
`AAssignErrors` error -8004
What I did:
I signed in on an iPhone using one of the secondary email addresses (not the primary one). It logged in, though with some restrictions (syncing didn't work).
After some time, I attempted to change the primary email address using the iPhone, switching it to one of the other addresses on the account. The change went through, and—interestingly—the original primary email became a secondary one. In other words, there had been a conflict.
Following this, I tried signing in on the MacBook using this new primary email address, and it worked!
Looking back at what happened, here is the explanation:
At some point, I had changed my primary email address via my iPhone, but it appears the change failed to sync with the MacBook (likely due to a bug in the new version of the OS).
By performing the same procedure again—this time using a more up-to-date version of iOS on the iPhone—the synchronization issue was resolved.
Therefore, if you are struggling to sign in and nothing happens, it is likely a conflict caused by a primary email address that failed to sync correctly.
Summary:
Do not change your primary email address via the website; instead, perform the change on an iPhone where the account is already signed in.
