diff --git a/src/at/nsid.gleam b/src/at/nsid.gleam
index 95a0c22..6631899 100644
--- a/src/at/nsid.gleam
+++ b/src/at/nsid.gleam
@@ -111,7 +111,8 @@ fn do_from_string(
     "" ->
       // The name segment must not start with a digit.
       case string.slice(input, slice_offset, slice_length) {
-        "1" <> _
+        "0" <> _
+        | "1" <> _
         | "2" <> _
         | "3" <> _
         | "4" <> _
@@ -171,7 +172,7 @@ fn do_from_string(
 
     // An authority segment cannot start or end with a hyphen.
     "-." <> _ -> Error(Nil)
-    "-" if slice_length == 0 -> Error(Nil)
+    "-" <> _ if slice_length == 0 -> Error(Nil)
 
     // The first authority segment cannot start with a digit.
     "0" <> _