Open the web.config file, then increase the value in minutes by using the time out attribute of SessionState element.
<system.web>
<sessionState timeout="300"></sessionState>
</system.web>
By default, the session timeout value is 20 minutes. Also in your case if you are using forms authentication, please check the timeout value.
<system.web>
<authentication mode="Forms">
<forms loginUrl="~/Account/Login" protection="All" path="/" timeout="300" />
</authentication>
</system.web>
Open IdentityConfig.cs, then change the value of the account logout time span that you want to change.
public class ApplicationUserManager : UserManager<CustomUser>
{
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var manager = new ApplicationUserManager(new UserStore<ApplicationUser>(context.Get<ApplicationDbContext>()));
// Configure user lockout defaults
manager.UserLockoutEnabledByDefault = true;
manager.DefaultAccountLockoutTimeSpan = TimeSpan.FromDays(1);
manager.MaxFailedAccessAttemptsBeforeLockout = 5;
return manager;
}
}