diff --git a/game/src/questmanager.cpp b/game/src/questmanager.cpp
index 8af4b32..fc23ed9 100644
--- a/game/src/questmanager.cpp
+++ b/game/src/questmanager.cpp
@@ -1724,14 +1724,20 @@ namespace quest
 
 	void CQuestManager::CancelServerTimers(DWORD arg)
 	{
-		itertype(m_mapServerTimer) it = m_mapServerTimer.begin();
-		for ( ; it != m_mapServerTimer.end(); ++it) {
-			if (it->first.second == arg) {
-				LPEVENT event = it->second;
-				event_cancel(&event);
-				m_mapServerTimer.erase(it);
-			}
-		}
+        vector<pair<string, DWORD>> timersToDelete;
+
+        // Find server timers that need deleting
+        for (auto& kv: m_mapServerTimer) {
+            if (kv.first.second == arg) {
+                LPEVENT event = kv.second;
+                event_cancel(&event);
+                timersToDelete.push_back(kv.first);
+            }
+        }
+
+        // Delete all the required server timers
+        for (const auto &timer: timersToDelete)
+            m_mapServerTimer.erase(timer);
 	}
 
 	void CQuestManager::SetServerTimerArg(DWORD dwArg)