Hi Thomas,

Is there any information in the logging available? Also, do you mind sharing your code so I can test it locally as well?

the code compiles and runs. I can debug through both the WundermanPasswordChecker class and the UmbracoCustomOwinStartup class

public class WundermanPasswordChecker : IBackOfficeUserPasswordChecker
{
    public Task<BackOfficeUserPasswordCheckerResult> CheckPasswordAsync(BackOfficeIdentityUser user, string password)
    {
        if (password != "test")
        {
            return Task.FromResult(BackOfficeUserPasswordCheckerResult.InvalidCredentials);
        }

        return Task.FromResult(BackOfficeUserPasswordCheckerResult.ValidCredentials);

    }
}



public class UmbracoCustomOwinStartup
{
    public void Configuration(IAppBuilder app)
    {
        ApplicationContext applicationContext = ApplicationContext.Current;
        app.ConfigureUserManagerForUmbracoBackOffice<BackOfficeUserManager, BackOfficeIdentityUser>(
            applicationContext,
            (options, context) =>
            {
                var membershipProvider = Umbraco.Core.Security.MembershipProviderExtensions.GetUsersMembershipProvider().AsUmbracoMembershipProvider();
                var settingContent = Umbraco.Core.Configuration.UmbracoConfig.For.UmbracoSettings().Content;
                var userManager = BackOfficeUserManager.Create(
                    options,
                    applicationContext.Services.UserService,
                    applicationContext.Services.EntityService,
                    applicationContext.Services.ExternalLoginService,
                    membershipProvider,
                    settingContent);
                userManager.BackOfficeUserPasswordChecker = new WundermanPasswordChecker();
                return userManager;
            }
        );
    }
}

Running in a newly installed VS2017 web project installed via nuget

The log files does not show anything related to this. In fact nothing is written to the log during the login phase

is working on a reply...