How to set asp.net Identity cookies expires time

In order to achieve the feature you are describing in ASP.NET Core 3.1, I configure authentication in Startup in the following way:

        services.ConfigureApplicationCookie(o =>
        {
            ...
            o.ExpireTimeSpan = TimeSpan.FromMinutes(30);
            o.SlidingExpiration = true;
            ...
            o.Events.OnSigningIn = ctx =>
            {
                if (ctx.Properties.IsPersistent)
                {
                    var issued = ctx.Properties.IssuedUtc ?? DateTimeOffset.UtcNow;
                    ctx.Properties.ExpiresUtc = issued.AddDays(14);
                }
                return Task.FromResult(0);
            };
        });

Using the OnSigningIn callback, I explicitly set the expiration date to now + 14 days if the "isPersistent" check-box is clicked.

Use this...

public void ConfigureAuth(IAppBuilder app)
{
  app.UseCookieAuthentication(new CookieAuthenticationOptions
  {
      ExpireTimeSpan = TimeSpan.FromHours(1),
  });            
}

If IsPersistent property of AuthenticationProperties is set to false, then the cookie expiration time is set to Session.

If checkbox "remember me" is checked then AuthenticationManager.SignIn(new AuthenticationProperties{ IsPersistent = true }, userIdentity); will create a cookie with expiration time equal to ExpireTimeSpan you set up in Startup.cs (defaults to 14days).

If checkbox "remember me" is NOT checked then you have to use AuthenticationManager.SignIn(new AuthenticationProperties{ IsPersistent = true, ExpiresUtc = DateTimeOffset.UtcNow.AddMinutes(30)}, userIdentity);. Again IsPersistent is set to true but now we give a value to ExpiresUtc so it does not use from CookieAuthenticationOptions from Startup.cs.

public override async Task SignInAsync(ApplicationUser user, bool isPersistent, bool rememberBrowser)
{
    var userIdentity = await CreateUserIdentityAsync(user).WithCurrentCulture();
    // Clear any partial cookies from external or two factor partial sign ins
    AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie, DefaultAuthenticationTypes.TwoFactorCookie);
    if (rememberBrowser)
    {
        var rememberBrowserIdentity = AuthenticationManager.CreateTwoFactorRememberBrowserIdentity(ConvertIdToString(user.Id));
        AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = isPersistent }, userIdentity, rememberBrowserIdentity);
    }
    else
    {
        //AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = isPersistent }, userIdentity);
        if (isPersistent)
        {
            AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = true }, userIdentity);
        }
        else
        {
            AuthenticationManager.SignIn(new AuthenticationProperties { IsPersistent = true, ExpiresUtc = DateTimeOffset.UtcNow.AddMinutes(30) }, userIdentity);
        }        
    }
}