diff --git a/ArchiSteamFarm/Bot.cs b/ArchiSteamFarm/Bot.cs
index 8ba4c5f5c..49cb78613 100755
--- a/ArchiSteamFarm/Bot.cs
+++ b/ArchiSteamFarm/Bot.cs
@@ -36,7 +36,6 @@ using ArchiSteamFarm.Localization;
 using ArchiSteamFarm.NLog;
 using ArchiSteamFarm.Plugins;
 using JetBrains.Annotations;
-using Microsoft.OpenApi.Models;
 using Newtonsoft.Json;
 using SteamKit2;
 using SteamKit2.Unified.Internal;
@@ -2195,32 +2194,6 @@ namespace ArchiSteamFarm {
 			await Actions.AcceptGuestPasses(guestPassIDs).ConfigureAwait(false);
 		}
 
-		private bool ShouldAckGroupChatMessage(ulong steamID) {
-			if (BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkReceivedMessagesAsRead)) {
-				return true;
-			}
-
-			if (BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkBotMessagesAsRead) &&
-				Bots.Values.Any(bot => bot.SteamID == steamID)) {
-				return true;
-			}
-
-			return false;
-		}
-
-		private bool ShouldAckPrivateChatMessage(ulong steamID, string message) {
-			if (ShouldAckGroupChatMessage(steamID)) {
-				return true;
-			}
-
-			if (BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkTradeMessagesAsRead) &&
-				message.StartsWith("[tradeoffer", StringComparison.Ordinal)) {
-				return true;
-			}
-
-			return false;
-		}
-
 		private async Task OnIncomingChatMessage(CChatRoom_IncomingChatMessage_Notification notification) {
 			if (notification == null) {
 				ArchiLogger.LogNullError(nameof(notification));
@@ -2955,6 +2928,34 @@ namespace ArchiSteamFarm {
 			StopPlayingWasBlockedTimer();
 		}
 
+		private bool ShouldAckGroupChatMessage(ulong steamID) {
+			if ((steamID == 0) || !new SteamID(steamID).IsIndividualAccount) {
+				ArchiLogger.LogNullError(nameof(steamID));
+
+				return false;
+			}
+
+			if (BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkReceivedMessagesAsRead)) {
+				return true;
+			}
+
+			return BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkBotMessagesAsRead) && Bots.Values.Any(bot => bot.SteamID == steamID);
+		}
+
+		private bool ShouldAckPrivateChatMessage(ulong steamID, string message) {
+			if ((steamID == 0) || !new SteamID(steamID).IsIndividualAccount || string.IsNullOrEmpty(message)) {
+				ArchiLogger.LogNullError(nameof(steamID) + " || " + nameof(message));
+
+				return false;
+			}
+
+			if (ShouldAckGroupChatMessage(steamID)) {
+				return true;
+			}
+
+			return BotConfig.BotBehaviour.HasFlag(BotConfig.EBotBehaviour.MarkTradeMessagesAsRead) && message.StartsWith("[tradeoffer", StringComparison.Ordinal);
+		}
+
 		private void StopConnectionFailureTimer() {
 			if (ConnectionFailureTimer == null) {
 				return;