I have not been able to sync one of my two email accounts in Outlook and the Windows Mail app.
My live.com accounts syncs OK.
My custom domain account doesn't. I can log on to outlook.com and read my mail for this account but not in Outlook or the Mail app.
I have checked my domain alias and it IS Primary.
This problem occurs on several machines, including a Windows 10 phone.
Two are on Windows 10 Insider Fast track. One desktop is not.
I have created/recreated the account in the Mail app.
When I try to sync it I get:
Something went wrong
We can't sync with m.Hotmail.com at the moment. Wait a while, then try again.
Note: Server Settings in Outlook app is eas.outlook.com
I am loathe to delete the account in Outlook app and recreate as I might loose my mail history.
This is a desperate issue as this account is the one I use for such things as my MVP and OEM communications with Microsoft.