diff --git a/packages/javascript-api/src/lib/services/graphql/__tests__/graphql-subscriptions.spec.ts b/packages/javascript-api/src/lib/services/graphql/__tests__/graphql-subscriptions.spec.ts
index 5769301f..bc642763 100644
--- a/packages/javascript-api/src/lib/services/graphql/__tests__/graphql-subscriptions.spec.ts
+++ b/packages/javascript-api/src/lib/services/graphql/__tests__/graphql-subscriptions.spec.ts
@@ -898,17 +898,23 @@ describe('GraphQL subscriptions', () => {
         sendErrorMessages();
       }
 
-      expect(subscriptionErrorSpy).toHaveBeenCalledWith(
-        expect.objectContaining({
+      expect(subscriptionErrorSpy).toHaveBeenCalledWith<
+        [QminderGraphQLError[]]
+      >([
+        {
           message: 'Subscription failed after 5 retries',
-        }),
-      );
+          errorType: 'ERROR',
+        },
+      ] satisfies QminderGraphQLError[]);
 
-      expect(subscription2ErrorSpy).toHaveBeenCalledWith(
-        expect.objectContaining({
+      expect(subscription2ErrorSpy).toHaveBeenCalledWith<
+        [QminderGraphQLError[]]
+      >([
+        {
           message: 'Subscription failed after 5 retries',
-        }),
-      );
+          errorType: 'ERROR',
+        },
+      ]);
 
       subscription.unsubscribe();
       subscription2.unsubscribe();
diff --git a/packages/javascript-api/src/lib/services/graphql/graphql.service.ts b/packages/javascript-api/src/lib/services/graphql/graphql.service.ts
index b030ee8d..8d5ed614 100644
--- a/packages/javascript-api/src/lib/services/graphql/graphql.service.ts
+++ b/packages/javascript-api/src/lib/services/graphql/graphql.service.ts
@@ -38,13 +38,13 @@ function parseQuery(queryOrDocumentNode: string | DocumentNode): string {
 }
 
 export interface QminderGraphQLError {
-  message: string;
-  errorType?: string | null;
-  extensions?: GraphQLErrorExtensions | null;
-  sourcePreview?: string | null;
-  offendingToken?: string | null;
-  locations?: SourceLocation[] | null;
-  path?: (string | number)[] | null;
+  readonly message: string;
+  readonly errorType?: string | null;
+  readonly extensions?: GraphQLErrorExtensions | null;
+  readonly sourcePreview?: string | null;
+  readonly offendingToken?: string | null;
+  readonly locations?: SourceLocation[] | null;
+  readonly path?: (string | number)[] | null;
 }
 
 interface Message {
@@ -756,11 +756,12 @@ export class GraphqlService {
           const subscriber = this.messagesSubscribers.get(messageId);
           this.cleanUpSubscription(messageId);
 
-          subscriber?.error(
-            new Error(
-              `Subscription failed after ${this.retryableErroredSubscriptionsRetryCount} retries`,
-            ),
-          );
+          subscriber?.error([
+            {
+              message: `Subscription failed after ${this.retryableErroredSubscriptionsRetryCount} retries`,
+              errorType: 'ERROR',
+            },
+          ] satisfies QminderGraphQLError[]);
         }
       });
   }