diff --git a/files/routes/posts.py b/files/routes/posts.py
index c9efe9a9f..2d11f2e1b 100644
--- a/files/routes/posts.py
+++ b/files/routes/posts.py
@@ -605,7 +605,7 @@ def thumbnail_thread(pid):
 
 	fetch_url = post.url
 
-	if fetch_url.startswith('/'): fetch_url = request.host_url[:-1] + fetch_url
+	if fetch_url.startswith('/'): fetch_url = f"https://{site}{fetch_url}"
 
 	headers={"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.72 Safari/537.36"}