diff --git a/backend/app/dav/caldav.py b/backend/app/dav/caldav.py
index 698dcd2..7ba0de9 100644
--- a/backend/app/dav/caldav.py
+++ b/backend/app/dav/caldav.py
@@ -343,11 +343,13 @@ def report(subpath):
         return _xml_response(multistatus)
 
     if tag == _qn('c', 'calendar-query'):
-        # Parse optional time-range
+        # Parse optional time-range. start ohne end = "ab jetzt offen";
+        # end ohne start = "bis X"; beide None = kein Filter.
         start, end = _extract_time_range(root)
         q = CalendarEvent.query.filter_by(calendar_id=cal.id)
-        if start is not None:
+        if end is not None:
             q = q.filter(CalendarEvent.dtstart < end)
+        if start is not None:
             q = q.filter(
                 (CalendarEvent.dtend >= start) | (CalendarEvent.dtstart >= start)
                 | (CalendarEvent.recurrence_rule.isnot(None))
@@ -368,17 +370,22 @@ def _extract_time_range(root: ET.Element):
         if not s:
             return None
         s = s.replace('Z', '+00:00')
+        dt = None
         try:
-            return datetime.fromisoformat(s)
+            dt = datetime.fromisoformat(s)
         except ValueError:
-            # Compact ICS form: 20260412T120000Z
             try:
-                return datetime.strptime(s, '%Y%m%dT%H%M%S%z')
+                dt = datetime.strptime(s, '%Y%m%dT%H%M%S%z')
             except ValueError:
                 try:
-                    return datetime.strptime(s[:15], '%Y%m%dT%H%M%S').replace(tzinfo=timezone.utc)
+                    dt = datetime.strptime(s[:15], '%Y%m%dT%H%M%S').replace(tzinfo=timezone.utc)
                 except ValueError:
                     return None
+        # Unsere DB-Spalten sind tz-naive (lokal UTC) - Vergleich ginge
+        # sonst mit TypeError. Also tz-Info abstreifen.
+        if dt.tzinfo is not None:
+            dt = dt.astimezone(timezone.utc).replace(tzinfo=None)
+        return dt
     return parse(tr.get('start')), parse(tr.get('end'))