It will depend upon your first call to get authenticated. You should get back a refresh token from ADAL returned when you make an authorize request for the user.
AuthenticationContext authenticationContext = new AuthenticationContext(Constants.AuthString, false);
AuthenticationResult userAuthnResult = authenticationContext.AcquireToken(Constants.ResourceUrl,
Constants.ClientIdForUserAuthn, redirectUri, PromptBehavior.Always);
If you examine the AuthenticationResult object, you will notice that it contains a refresh token.
You can look at the following article ADAL, Windows Azure AD and Multi-Resource Refresh Tokens:
ADAL, Windows Azure AD and Multi-Resource Refresh Tokens
That provides more information.
If you require more assistance with this issue, it may be best to create an Azure Developer support case using the Azure Management portal. At that point, we can gather information that is more specific to your tenant and that information is not
appropriate to share on a public forum.
Regards,
~ MIMUSH (MSFTE)