Initial setup cannot see remote repostories; GitHub desktop OK

[Mark Modig]

Trying to set up Sourcetree to pick up company repositories. If I log in to Github Desktop, they show up fine. 

I tried setting up an account in Sourcetree, but does not seem to work. Try with Github.com- try both HTTPS and SSH. If I try with OAuth authentication, I get a new tab on my browser that is blank, and seems to succeed in Sourcetree, but no repositories are listed.
If I try basic, and refresh password, I enter password and I get authentication failed
Failed to check login for user [xxxx]
Requires authentication

But I know password is correct because it works fine in GithubDesktop. I'd rather use Sourcetree because I have some experience using it and I like it.

What am I missing?

[Mark Modig]

Update:
On a new tab: I click Remote subtab- get Remote Repositories pane. 
My account is listed with a Red X. Right click on it gives Edit Account... tooltip. Click on it.
Pops up "Edit Hosting Account":
Host
Hosting Service: GitHub
Host URL: https://github.com/
Preferred Protocol: HTTPS
Credentials
Authentication: OAuth
Username: XXX
Refresh OAuth Token

Click that, and get a new blank tab in browser.
Underneath Credentials section says:Authentication OK with a green check.
Click OK.

Back to Remote Repositories screen.
No repositories listed. If I click refresh, account on left side gets Red X.
Mouse over avatar in account list on left returns:
Tooltip with:
Unable to read repositories for the user from the remote host
Failed to list repositories for user [xxx]
Validation failed.

I can go through the whole OAuth rigamarole and the red X goes away- until I click on Refresh again.

As I said, I can login to GitHub Desktop just fine- it sees the remote repositories. But Sourcetree can't seem to hook up. What am I missing?