diff --git a/src/errors.h b/src/errors.h
index 18d3f0c..00f7df0 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -2268,7 +2268,7 @@
 EXTERN char e_nfa_regexp_not_enough_space_to_store_whole_nfa[]
 	INIT(= N_("E876: (NFA regexp) Not enough space to store the whole NFA"));
 EXTERN char e_nfa_regexp_invalid_character_class_nr[]
-	INIT(= "E877: (NFA regexp) Invalid character class: %d");
+	INIT(= N_("E877: (NFA regexp) Invalid character class: %d"));
 EXTERN char e_nfa_regexp_could_not_allocate_memory_for_branch_traversal[]
 	INIT(= N_("E878: (NFA regexp) Could not allocate memory for branch traversal!"));
 #ifdef FEAT_SYN_HL