diff --git a/src/main/kotlin/org/web3j/quorum/enclave/EnclaveClientConnectionException.kt b/src/main/kotlin/org/web3j/quorum/enclave/EnclaveClientConnectionException.kt
new file mode 100644
index 0000000..aa0f51a
--- /dev/null
+++ b/src/main/kotlin/org/web3j/quorum/enclave/EnclaveClientConnectionException.kt
@@ -0,0 +1,5 @@
+package org.web3j.quorum.enclave
+
+import org.web3j.protocol.exceptions.ClientConnectionException
+
+class EnclaveClientConnectionException(message: String) : ClientConnectionException(message)
\ No newline at end of file
diff --git a/src/main/kotlin/org/web3j/quorum/enclave/protocol/http/EnclaveHttpService.kt b/src/main/kotlin/org/web3j/quorum/enclave/protocol/http/EnclaveHttpService.kt
index b458eb4..27c3e24 100644
--- a/src/main/kotlin/org/web3j/quorum/enclave/protocol/http/EnclaveHttpService.kt
+++ b/src/main/kotlin/org/web3j/quorum/enclave/protocol/http/EnclaveHttpService.kt
@@ -5,26 +5,26 @@ import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import org.web3j.quorum.enclave.protocol.EnclaveService
 import okhttp3.*
 import okhttp3.OkHttpClient
+import org.web3j.quorum.enclave.EnclaveClientConnectionException
 
 
 /**
  * EnclaveHttpService implements send methods that support communication with the private enclave via Http.
  * Currently Http communication is only supported in Tessera.
  */
-class EnclaveHttpService(private val url: String, private val port: Int) : EnclaveService {
+class EnclaveHttpService(private val url: String, private val port: Int, private val client: OkHttpClient = OkHttpClient()) : EnclaveService {
 
     private val objectMapper = jacksonObjectMapper()
             .setSerializationInclusion(JsonInclude.Include.NON_NULL)
-    private val JSON = MediaType.parse("application/json; charset=utf-8")
+    private val JSON_MEDIA_TYPE = MediaType.parse("application/json; charset=utf-8")
 
     /**
      * Send a new raw payload to Enclave
      */
     override fun <S, T> send(request: S, path: String, responseType: Class<T>): T {
         val payload = objectMapper.writeValueAsString(request)
-        val client = OkHttpClient()
         val uri = "$url:$port/$path"
-        val body = RequestBody.create(JSON, objectMapper.writeValueAsString(payload))
+        val body = RequestBody.create(JSON_MEDIA_TYPE, payload)
         val request = Request.Builder()
                 .url(uri)
                 .post(body)
@@ -32,8 +32,15 @@ class EnclaveHttpService(private val url: String, private val port: Int) : Encla
 
         val response = client.newCall(request).execute()
 
-        val chunk = response.body().toString()
-        return objectMapper.readValue(chunk, responseType)
+        if(response.isSuccessful) {
+            val chunk = response.body()?.string()
+            return objectMapper.readValue(chunk, responseType)
+        } else {
+            val statusCode = response.code()
+            val text = if (response.body() == null) "N/A" else response.body()?.string()
+
+            throw EnclaveClientConnectionException("Invalid response received from enclave: $statusCode $text")
+        }
     }
 
     /**