diff --git a/server.py b/server.py
index f51142e..9a8d57d 100644
--- a/server.py
+++ b/server.py
@@ -1,4 +1,5 @@
 import contextlib
+import datetime
 import io
 import json
 import os
@@ -221,19 +222,21 @@ def preview_url(
             for result in results:
                 # find the one with the closest timestamp
                 metadata, _ts = result
-                if ts is None or abs(ts - _ts) < 3600:
+                created_at = datetime.datetime.fromtimestamp(_ts)
+                if ts is None or created_at <= datetime.datetime.fromtimestamp(ts):
                     logging.debug("Optimal cache hit for %r", url)
                     return json.loads(metadata)
             else:
                 logging.debug("No optimal cache matches for url %r.", url)
                 # No close matches, get the latest one
                 metadata, _ts = results[-1]
+                created_at = datetime.datetime.fromtimestamp(_ts)
                 # If the latest one is more than a week old, re-fetch. Otherwise, return.
-                if ts is None or abs(ts - _ts) < 604800:
+                if ts is None or created_at < (datetime.datetime.now() - datetime.timedelta(days=7)):
                     logging.debug("Stale cache hit for %r", url)
                     return json.loads(metadata)
                 else:
-                    logging.debug("Cache miss for %r")
+                    logging.debug("Cache miss for %r", url)
         else:
             logging.debug("Full cache miss for %r", url)