For some reason i could not run SMTP and Basic Authentication on a new O365 account today, after hours of searching i found there is some default security settings that is set on the organisation security settings.
After a lot of more times searching i find this text: “You can enable Basic Auth support for a tenant from the Azure portal (Azure Active Directory -> Properties -> Manage Security defaults -> Enable Security defaults = No).”
And this worked for me after set Enable Security defaults to No i could runt SMTP and Basic Auth.