diff --git a/src/Nethermind/Nethermind.Serialization.Json/IntConverter.cs b/src/Nethermind/Nethermind.Serialization.Json/IntConverter.cs
index ebee61024f3..1edf445d735 100644
--- a/src/Nethermind/Nethermind.Serialization.Json/IntConverter.cs
+++ b/src/Nethermind/Nethermind.Serialization.Json/IntConverter.cs
@@ -16,7 +16,7 @@ private static int FromString(ReadOnlySpan<byte> s)
         {
             if (s.Length == 0)
             {
-                throw new JsonException("null cannot be assigned to long");
+                throw new JsonException("null cannot be assigned to int");
             }
 
             if (s.SequenceEqual("0x0"u8))
diff --git a/src/Nethermind/Nethermind.Serialization.Json/ULongConverter.cs b/src/Nethermind/Nethermind.Serialization.Json/ULongConverter.cs
index 08d9afa23f2..a2637fb085c 100644
--- a/src/Nethermind/Nethermind.Serialization.Json/ULongConverter.cs
+++ b/src/Nethermind/Nethermind.Serialization.Json/ULongConverter.cs
@@ -19,7 +19,7 @@ public static ulong FromString(ReadOnlySpan<byte> s)
         {
             if (s.Length == 0)
             {
-                throw new JsonException("null cannot be assigned to long");
+                throw new JsonException("null cannot be assigned to ulong");
             }
 
             if (s.SequenceEqual("0x0"u8))