diff --git a/src/types/rpc.ts b/src/types/rpc.ts
index 984aa65..83768ec 100644
--- a/src/types/rpc.ts
+++ b/src/types/rpc.ts
@@ -1,8 +1,13 @@
 // Basic structure of the JSON-RPC response
-export interface JSONRPCResponse {
+export interface JSONRPCResponse<T> {
   jsonrpc: string;
-  result: Result;
-  id: string;
+  id: number | string | null;
+  result?: T;
+  error?: {
+    code: number;
+    message: string;
+    data?: unknown;
+  };
 }
 
 // Result contains various fields like final execution status, an array of receipts, etc.
diff --git a/src/utils/signature.ts b/src/utils/signature.ts
index b638843..cc3b3fc 100644
--- a/src/utils/signature.ts
+++ b/src/utils/signature.ts
@@ -30,27 +30,20 @@ export async function signatureFromTxHash(
     },
     body: JSON.stringify(payload),
   });
+  if (!response.ok) {
+    throw new Error(`HTTP error! status: ${response.status}`);
+  }
+
+  const json: JSONRPCResponse<FinalExecutionOutcome> = await response.json();
 
-  const jsonResponse = (await response.json()) as JSONRPCResponse;
-  let base64Sig = jsonResponse.result.status?.SuccessValue;
-  // TODO: Find an example when successValue isn't available and we need to enter this block.
-  if (base64Sig === "") {
-    // Extract receipts_outcome
-    const receiptsOutcome = jsonResponse.result.receipts_outcome;
-    // Map to get SuccessValue
-    const successValues = receiptsOutcome.map(
-      // eslint-disable-next-line
-      (outcome: any) => outcome.outcome.status.SuccessValue
-    );
-    // Find the first non-empty value
-    base64Sig = successValues.find((value) => value && value.trim().length > 0);
+  if (json.error) {
+    throw new Error(`JSON-RPC error: ${json.error.message}`);
   }
-  if (base64Sig) {
-    const decodedValue = Buffer.from(base64Sig, "base64").toString("utf-8");
-    const signature: MPCSignature = JSON.parse(decodedValue);
-    return transformSignature(signature);
+
+  if (json.result) {
+    return signatureFromOutcome(json.result);
   } else {
-    throw new Error(`No valid values found in transaction receipt ${txHash}`);
+    throw new Error(`No FinalExecutionOutcome in response: ${json}`);
   }
 }
 
@@ -70,8 +63,13 @@ export function signatureFromOutcome(
   outcome: FinalExecutionOutcome | Partial<FinalExecutionOutcome>
 ): Signature {
   // TODO: Find example outcome when status is not of this casted type.
-  const b64Sig = (outcome.status as FinalExecutionStatus).SuccessValue!;
-  const decodedValue = Buffer.from(b64Sig, "base64").toString("utf-8");
-  const signature = JSON.parse(decodedValue);
-  return transformSignature(signature);
+  const b64Sig = (outcome.status as FinalExecutionStatus).SuccessValue;
+  if (b64Sig) {
+    const decodedValue = Buffer.from(b64Sig, "base64").toString("utf-8");
+    const signature = JSON.parse(decodedValue);
+    return transformSignature(signature);
+  }
+  throw new Error(
+    `No detectable signature found in transaction ${outcome.transaction_outcome?.id}`
+  );
 }
diff --git a/tests/unit/utils.signature.test.ts b/tests/unit/utils.signature.test.ts
index a9d8fb8..843dc14 100644
--- a/tests/unit/utils.signature.test.ts
+++ b/tests/unit/utils.signature.test.ts
@@ -18,22 +18,15 @@ describe("utility: get Signature", () => {
     });
   });
 
-  // Still need a NEW example of this!
-  // it("successful: alternative signatureFromTxHash", async () => {
-  //   const sig = await signatureFromTxHash(
-  //     url,
-  //     "EK4XUwyR29w6eaSfSSPb8he3y7nkTQSbYJVXgSx5vZ4T"
-  //   );
-  //   expect(sig).toEqual({
-  //     big_r:
-  //       "024598E193A9377B98A5B4621BA81FDEEA9DED3E3E7F41C073D0537BC2769C10FC",
-  //     big_s: "65D23B4EA333FFC5486FA295B7AEAB02EACA4E35E22B55108563A63199B96558",
-  //   });
-  // });
-
-  it("failed: signatureFromTxHash", async () => {
+  it("signatureFromTxHash fails with no signature", async () => {
     await expect(signatureFromTxHash(url, failedHash)).rejects.toThrow(
-      `No valid values found in transaction receipt ${failedHash}`
+      `No detectable signature found in transaction ${failedHash}`
+    );
+  });
+
+  it("signatureFromTxHash fails with parse error", async () => {
+    await expect(signatureFromTxHash(url, "nonsense")).rejects.toThrow(
+      "JSON-RPC error: Parse error"
     );
   });