diff --git a/src/errors.ts b/src/errors.ts
index 094f391..7181160 100644
--- a/src/errors.ts
+++ b/src/errors.ts
@@ -1,9 +1,9 @@
 import { JsonRpcError, EthereumProviderError } from './classes';
 import { errorCodes } from './error-constants';
-import type { DataWithOptionalCause } from './utils';
+import type { DataWithOptionalCause, OptionalDataWithOptionalCause } from './utils';
 import { getMessageFromCode } from './utils';
 
-type EthereumErrorOptions<Data extends DataWithOptionalCause> = {
+type EthereumErrorOptions<Data extends OptionalDataWithOptionalCause> = {
   message?: string;
   data?: Data;
 };
@@ -15,7 +15,7 @@ type ServerErrorOptions<Data extends DataWithOptionalCause> = {
 type CustomErrorArg<Data extends DataWithOptionalCause> =
   ServerErrorOptions<Data>;
 
-type JsonRpcErrorsArg<Data extends DataWithOptionalCause> =
+type JsonRpcErrorsArg<Data extends OptionalDataWithOptionalCause> =
   | EthereumErrorOptions<Data>
   | string;
 
@@ -65,7 +65,7 @@ export const rpcErrors = {
    * @param arg - The error message or options bag.
    * @returns An instance of the {@link JsonRpcError} class.
    */
-  internal: <Data extends DataWithOptionalCause>(
+  internal: <Data extends OptionalDataWithOptionalCause>(
     arg?: JsonRpcErrorsArg<Data>,
   ) => getJsonRpcError(errorCodes.rpc.internal, arg),
 
@@ -245,7 +245,7 @@ export const providerErrors = {
  * @param arg - The error message or options bag.
  * @returns An instance of the {@link JsonRpcError} class.
  */
-function getJsonRpcError<Data extends DataWithOptionalCause>(
+function getJsonRpcError<Data extends OptionalDataWithOptionalCause>(
   code: number,
   arg?: JsonRpcErrorsArg<Data>,
 ): JsonRpcError<Data> {
@@ -278,7 +278,7 @@ function getEthProviderError<Data extends DataWithOptionalCause>(
  * @param arg - The error message or options bag.
  * @returns A tuple containing the error message and optional data.
  */
-function parseOpts<Data extends DataWithOptionalCause>(
+function parseOpts<Data extends OptionalDataWithOptionalCause>(
   arg?: JsonRpcErrorsArg<Data>,
 ): [message?: string | undefined, data?: Data | undefined] {
   if (arg) {