diff --git a/src/services/source_health.py b/src/services/source_health.py
index e6b1cdd..9837cda 100644
--- a/src/services/source_health.py
+++ b/src/services/source_health.py
@@ -112,6 +112,10 @@ async def _check_source_reachability(
     checks = []
     url = source["url"]
 
+    # URL-Schema sicherstellen: t.me-Kanaele und andere Domains koennen ohne https:// vorkommen
+    if url and not url.startswith(("http://", "https://")):
+        url = "https://" + url.lstrip("/")
+
     try:
         resp = await client.get(url)