diff --git a/src/identityApiClient.ts b/src/identityApiClient.ts
index 7d6f3d0f1..5af3cc4a1 100644
--- a/src/identityApiClient.ts
+++ b/src/identityApiClient.ts
@@ -173,7 +173,7 @@ export default function IdentityAPIClient(
 
         if (mpInstance._Store.identityCallInFlight) {
             invokeCallback(
-                callback as Callback,
+                callback,
                 HTTPCodes.activeIdentityRequest,
                 'There is currently an Identity request processing. Please wait for this to return before requesting again'
             );
@@ -234,11 +234,13 @@ export default function IdentityAPIClient(
                 false
             );
         } catch (err) {
+            const errorMessage = (err as Error).message || 'Unknown Error';
+
             mpInstance._Store.identityCallInFlight = false;
             invokeCallback(
-                callback as Callback,
+                callback,
                 HTTPCodes.noHttpCoverage,
-                err.toString()
+                errorMessage,
             );
             error('Error sending identity request to servers' + ' - ' + err);
         }
diff --git a/src/sdkRuntimeModels.ts b/src/sdkRuntimeModels.ts
index 8a75191dc..cb94f7d56 100644
--- a/src/sdkRuntimeModels.ts
+++ b/src/sdkRuntimeModels.ts
@@ -3,7 +3,6 @@ import { DataPlanVersion } from '@mparticle/data-planning-models';
 import {
     MPConfiguration,
     MPID,
-    Callback,
     IdentityApiData,
 } from '@mparticle/web-sdk';
 import { IStore } from './store';
@@ -287,7 +286,7 @@ export interface SDKHelpersApi {
     ): boolean;
     isObject?(item: any);
     invokeCallback?(
-        callback: Callback,
+        callback: IdentityCallback,
         code: number,
         body: string,
         mParticleUser?: IMParticleUser,
diff --git a/test/src/tests-identityApiClient.ts b/test/src/tests-identityApiClient.ts
index 568305fb4..4cc7d0608 100644
--- a/test/src/tests-identityApiClient.ts
+++ b/test/src/tests-identityApiClient.ts
@@ -181,7 +181,7 @@ describe('Identity Api Client', () => {
         it('should call invokeCallback with an error if the fetch fails', async () => {
             fetchMock.post(urls.identify, {
                 status: 500,
-                throws: 'server error',
+                throws: { message: 'server error' },
             }, {
                 overwriteRoutes: true,
             });