Can't add Google or Yahoo email accounts to Internet Accounts pane.

Ok, we sort of finally found the main problem, but we still can't fix that main problem outright, but there is a good main problem workaround.

-The "add other account" mail workaround posted above is still good.

-The "clean install" test also posted above is confirmed.

If you are on High Sierra, and you want to use the main problem workaround instead of just using the mail workaround, keep reading. I highly recommend it, as the main problem can cause multiple errors in multiple places, beyond the few examples I will add below.

The Problem:

It seems there is something local stopping connections to at least swscan.apple.com, but we don't know what/where it is in order to fix it in-place. I'm still looking, but it's mostly over my head now.

Do you have the same main problem?

1. First, I suspect you have to be on High Sierra to have this problem. I installed multiple Mojaves and they were all error-free.

2. Second, take a look at these related errors to the problem. Errors 1-3 are the easiest to test for, but maybe some of the other errors already look familiar.

1) Can't add Google or Yahoo email accounts to Internet Accounts pane. (this thread)

2) Software Update failing on High Sierra: (NSURLErrorDomain error -1012.)

3) iOS 17, iPhone 12 not showing up on 2009 iMac iTunes*

aka. iOS 17/new iPhones can't connect to iTunes. Support files won't download*.

*make sure you have iTunes 12.8.3 if you test this one.

4) Can't download High Sierra full installer.

5) other unspecified "server" or "connection" errors.

3. Third, do 1-3 occur together? If you have 1 or 2 of the errors, but a 3rd one works fine, you likely don't have the problem described above, and this solution would be overkill.

The Solution:

1. 1. The current best solution is to install a clean copy of High Sierra. The clean install test I previously posted was right on the money, and was reproducible during testing.
   2. Migrate your users and data into the clean copy, but to avoid ugly permissions problems, try following the outline found here: Is there a difference in results between Migration Assistant app and 'Transfer Information' option during OS installation?
   3. The High Sierra installer installs an older version of iTunes. You want to install the latest version of iTunes or you may have iOS device connection issues. On High Sierra this should be iTunes 12.8.3. Get it here: Download iTunes 12.8.3 for Mac
   4. After install and account migration, check SystemPreferences>InternetAccounts> and choose the "Google" or "Yahoo" account set up option. If you still get blank windows and error messages, don't panic, just restart your system once, and check again.

John Galt wrote:

I have an answer but you won't like it. A new or existing Yahoo! Mail Account may no longer be installed on a Mac running High Sierra (and presumably earlier versions).

It has nothing to do with network configurations, proxy settings, or anything else. Yahoo! (and presumably Google) now use authentication methods that are not incorporated in High Sierra.

At least that explains the harassing password requests, and obviates the need to reinstall High Sierra. Apple should have known better than to waste your time with that.

I actually have multiple yahoo and multiple google accounts. Only 2 had the original password prompt that led to an error. The others are all still working fine.

There IS a workaround to get Google accounts back in (I didn't try this on the Yahoo account), but it loses a few features. Go to SystemPreferences>InternetAccounts> and scroll down the right side to "Add Other Account...", click.

Click "Mail Account" at top of right side.

Enter your details, BUT YOU NEED TO GET A NEW APP-SPECIFIC PASSWORD from your google mail account online. It's easier to google where to find that than for me to explain it. Click "sign in".

Your account will show up on left, with the different icon. See the blue "@" icon next to mine at the bottom of the list.

Here's the only difference I have seen so far. If you select your account on the left, this will appear on the right. You only have Mail and Notes. Normally, you should also have Calendars and Contacts.

Hope that helps someone out of a jam.

I did a clean install of High Sierra, and went into Mail to try fixing this the right way. I got DIFFERENT behavior!

At the moment, the Yahoo function is down and I can't test it.

But the Google account, when I try to add it to Mail, I get the following window now instead of the "Connection Insecure" error dialogue:

and scrolled further down:

the "Learn More" link goes to the page: https://support.google.com/accounts/answer/12379384

I have no idea why all this info didn't appear until I used a clean install of the exact same OS that wouln't show it.

*I noticed this thread doesn't display correctly when viewed on a mobile browser. It will be missing picture and text, even when text is extended with the "more" option. Try viewing it on a desktop browser if it doesn't make sense or seems incomplete.*