diff --git a/wasm/src/service_api.rs b/wasm/src/service_api.rs
index db44775..9188b95 100644
--- a/wasm/src/service_api.rs
+++ b/wasm/src/service_api.rs
@@ -40,7 +40,7 @@ fn add_root(pk: String, weight: u32) -> AddRootResult {
     } else {
         return AddRootResult {
             ret_code: 1,
-            error: "Root could add only a host of trust graph service",
+            error: "Root could add only a host of trust graph service".to_string(),
         };
     }
 }
diff --git a/wasm/src/service_impl.rs b/wasm/src/service_impl.rs
index 034c857..054cd61 100644
--- a/wasm/src/service_impl.rs
+++ b/wasm/src/service_impl.rs
@@ -6,7 +6,7 @@ use std::convert::{Into, TryInto};
 use std::str::FromStr;
 use std::time::Duration;
 use thiserror::Error as ThisError;
-use trust_graph::{CertificateError, PublicKeyHashable, TrustGraphError};
+use trust_graph::{CertificateError, TrustGraphError};
 
 #[derive(ThisError, Debug)]
 pub enum ServiceError {