EWS Inbox Cleanup

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Exchange.WebServices.Data;
using static Microsoft.Exchange.WebServices.Data.SearchFilter;

namespace Inboxer
{
    class MainClass
    {
        public static void Main()
        {
            var service = new ExchangeService { Credentials = new WebCredentials("username", "password"), Url = new Uri("https://owa.check24.de/ews/exchange.asmx") };
            IList<ItemId> items = default;
            do
            {
                items = service.FindItems(WellKnownFolderName.Inbox, new ContainsSubstring(ItemSchema.Subject, "[PRTG Network Monitor]", ContainmentMode.Prefixed, ComparisonMode.Exact), new ItemView(byte.MaxValue) { PropertySet = PropertySet.FirstClassProperties })?.Select(item => item.Id).ToList();
                if (items?.Count > 0)
                {
                    Console.WriteLine($"Removing {items?.Count} items...");
                    service.DeleteItems(items, DeleteMode.HardDelete, default, default);
                    Console.WriteLine("Done");
                }
            }
            while (items?.Count > 0);
            Console.ReadLine();
        }
    }
}