We are using Umbraco 11 for frontend and experiencing an annoying backoffice auto logout after 30 minutes, even if you are using frontend. Tried many things. Tried also version 12.

Startup.cs

    var builder = services.AddUmbraco(_env, _config)
        .AddBackOffice()
        .AddShop()
        .AddWebsite()
        .AddComposers();

    services.ConfigureApplicationCookie(options =>
    {
        options.ExpireTimeSpan = TimeSpan.FromMinutes(120);
        options.SlidingExpiration = true;
    });

    services.AddSession(options => options.IdleTimeout = TimeSpan.FromMinutes(120));

Extending MemberSignInManager.cs

public override Task SignInWithClaimsAsync(MemberIdentityUser user,
    AuthenticationProperties? authenticationProperties, IEnumerable<Claim> additionalClaims)
{
    var ts = TimeSpan.FromMinutes(120);
    authenticationProperties.ExpiresUtc = DateTimeOffset.Now.Add(ts);
    authenticationProperties.AllowRefresh = false; // tried with true
    authenticationProperties.IsPersistent = false; // tried with true

    return base.SignInWithClaimsAsync(user, authenticationProperties, claims);
} 

appsettings.json

  "Umbraco": {
    "CMS": {
      "KeepAlive": {
        "DisableKeepAliveTask": false,
        "KeepAlivePingUrl": "~/api/keepalive/ping"
      },

Web.config

<configuration>
    <system.web>
        <compilation debug="true"  />
        <httpRuntime  />
        <sessionState mode="InProc" timeout="120"></sessionState>
        <authentication mode="Forms">
            <forms timeout="120" />
        </authentication>
    </system.web>
</configuration>

Can anybody give us some suggestions?