diff --git a/sanic/server.py b/sanic/server.py
index d83042eb..8d4b5db2 100644
--- a/sanic/server.py
+++ b/sanic/server.py
@@ -567,7 +567,7 @@ def serve(host, port, request_handler, error_handler, before_start=None,
         debug=debug,
     )
 
-    if isinstance(sock, str):
+    if hasattr(sock, '__fspath__'):
         server_coroutine = loop.create_unix_server(
             server,
             path=sock,