diff --git a/sube/src/builder.rs b/sube/src/builder.rs
index 6d6ca37..9910b82 100644
--- a/sube/src/builder.rs
+++ b/sube/src/builder.rs
@@ -204,12 +204,12 @@ async fn get_multi_backend_by_url<'a>(
             let backend = Box::new(get_backend_by_url(url.clone()).await?);
             let backend = Box::leak::<'static>(backend);
 
-            instance_backend.insert(base_path.clone(), backend);
+            instance_backend.insert(base_path.clone(), backend).map_err(|_| Error::CantInitBackend)?;
 
             let metadata = Box::new(get_metadata(backend, metadata).await?);
             let metadata = Box::leak::<'static>(metadata);
 
-            instance_metadata.insert(base_path.clone(), metadata);
+            instance_metadata.insert(base_path.clone(), metadata).map_err(|_| Error::BadMetadata)?;
 
             Ok((backend, metadata))
         }
diff --git a/sube/src/lib.rs b/sube/src/lib.rs
index c7d9315..d8ac9e9 100644
--- a/sube/src/lib.rs
+++ b/sube/src/lib.rs
@@ -488,6 +488,7 @@ pub enum Error {
     AccountNotFound,
     ConstantNotFound(String),
     Platform(String),
+    CantInitBackend
 }
 
 impl fmt::Display for Error {
diff --git a/sube/src/rpc.rs b/sube/src/rpc.rs
index 58cfef8..62f520e 100644
--- a/sube/src/rpc.rs
+++ b/sube/src/rpc.rs
@@ -106,9 +106,10 @@ impl<R: Rpc> Backend for RpcClient<R> {
         log::debug!("Extrinsic: {}", extrinsic);
 
         self.0
-            .rpc("author_submitExtrinsic", &[&format!("\"{}\"", &extrinsic)])
+            .rpc::<serde_json::Value>("author_submitExtrinsic", &[&format!("\"{}\"", &extrinsic)])
             .await
             .map_err(|e| crate::Error::Node(e.to_string()))?;
+
         Ok(())
     }