diff --git a/babel/messages/pofile.py b/babel/messages/pofile.py
index 68cb11b0a..ddf1a3fb5 100644
--- a/babel/messages/pofile.py
+++ b/babel/messages/pofile.py
@@ -249,7 +249,7 @@ def _finish_current_message(self) -> None:
         if self.messages:
             if not len(self.translations):
                 self.translations.append([0, _NormalizedString("")])
-                self._invalid_pofile("", self.offset, "invalid PO file provided")
+                self._invalid_pofile("", self.offset, "invalid po file provided")
             self._add_message()
 
     def _process_message_line(self, lineno, line, obsolete=False) -> None: