diff --git a/calibre-plugin/libby/client.py b/calibre-plugin/libby/client.py
index a5f639e..54f4647 100644
--- a/calibre-plugin/libby/client.py
+++ b/calibre-plugin/libby/client.py
@@ -323,6 +323,8 @@ def parse_datetime(value: str) -> Optional[datetime]:  # type: ignore[return]
             "%Y-%m-%dT%H:%M:%S.%fZ",
             "%Y-%m-%dT%H:%M:%S%z",
             "%Y-%m-%dT%H:%M:%S.%f%z",
+            "%Y-%m-%dT%H:%M:%S",
+            "%Y-%m-%dT%H:%M:%S.%f",            
             "%m/%d/%Y",  # publishDateText
         )
         for i, fmt in enumerate(formats, start=1):