For security purposes this account must be authenticated via OAuth, rather than with a password, since it was previously authenticated via OAuth

When authenticating an account using Microsoft Exchange, your end-user can get the following error message:

For security purposes this account must be authenticated
via OAuth, rather than with a password, since it was
previously authenticated via OAuth.

Causes

• The account was previously authenticated using Modern Authentication (OAuth) and your end-user is now trying to authenticate it again but using Basic Authentication (password). This is not supported.

Resolution

•  Have your end-user authenticate their account using the Office 365 option when using Hosted Authentication or pass `office365` as the `provider` when using Native Authentication.