diff --git a/packages/rpc/src/client/action.ts b/packages/rpc/src/client/action.ts
index 8ef4f4c91..4ac79e9b7 100644
--- a/packages/rpc/src/client/action.ts
+++ b/packages/rpc/src/client/action.ts
@@ -24,7 +24,7 @@ import {
     rpcResponseActionObservableSubscriptionError,
     rpcResponseActionType,
     RpcTypes,
-    WrappedV
+    WrappedV,
 } from '../model.js';
 import { rpcDecodeError, RpcMessage } from '../protocol.js';
 import { ClientProgress } from '../writer.js';
@@ -310,6 +310,9 @@ export class RpcActionClient {
                                 subject.release();
                                 const error = reply.getError();
                                 // console.debug('Client received error', error);
+                                for (const sub of Object.values(subscribers)) {
+                                    sub.error(error);
+                                }
                                 reject(error);
                                 break;
                             }
diff --git a/packages/rpc/src/client/client.ts b/packages/rpc/src/client/client.ts
index 71128a940..f74a20772 100644
--- a/packages/rpc/src/client/client.ts
+++ b/packages/rpc/src/client/client.ts
@@ -412,6 +412,7 @@ export class RpcBaseClient implements WritableClient {
         } else {
             const callback = this.replies.get(message.id);
             if (!callback) {
+                console.log(message.debug());
                 throw new Error('No callback for ' + message.id);
             }
             if (callback) callback(message);
diff --git a/packages/rpc/src/server/action.ts b/packages/rpc/src/server/action.ts
index eb61d6d47..ed4b7ed22 100644
--- a/packages/rpc/src/server/action.ts
+++ b/packages/rpc/src/server/action.ts
@@ -24,7 +24,7 @@ import {
     typeOf,
     TypeTuple,
     ValidationError,
-    ValidationErrorItem
+    ValidationErrorItem,
 } from '@deepkit/type';
 import { isObservable, Observable, Subject, Subscription } from 'rxjs';
 import { Collection, CollectionEvent, CollectionQueryModel, CollectionQueryModelInterface, CollectionState } from '../collection.js';
@@ -281,7 +281,7 @@ export class RpcServerAction {
                 const { types, classType, method } = observable;
                 const body = message.parseBody<rpcActionObservableSubscribeId>();
                 if (observable.subscriptions[body.id]) return response.error(new Error('Subscription already created'));
-                if (!types.observableNextSchema) return response.error(new Error('No observable type detected'));
+                if (!types.observableNextSchema) return response.error(new Error('No observable type on RPC action detected. No Observable<T> defined  or RxJS not nominal.'));
 
                 const sub: { active: boolean, sub?: Subscription, complete: () => void } = {
                     active: true,
@@ -335,7 +335,7 @@ export class RpcServerAction {
                 if (!observable) return response.error(new Error('No observable to unsubscribe found'));
                 const body = message.parseBody<rpcActionObservableSubscribeId>();
                 const sub = observable.subscriptions[body.id];
-                if (!sub) return response.error(new Error('No subscription found'));
+                if (!sub) return;
                 sub.active = false;
                 if (sub.sub) {
                     sub.sub.unsubscribe();
diff --git a/packages/rpc/tests/controller.spec.ts b/packages/rpc/tests/controller.spec.ts
index ba7888623..34c167f6e 100644
--- a/packages/rpc/tests/controller.spec.ts
+++ b/packages/rpc/tests/controller.spec.ts
@@ -1,10 +1,10 @@
 import { assertType, entity, Positive, ReflectionClass, ReflectionKind } from '@deepkit/type';
 import { expect, test } from '@jest/globals';
 import { DirectClient } from '../src/client/client-direct.js';
-import { getActions, rpc, rpcClass, RpcController } from '../src/decorators.js';
+import { getActions, rpc, RpcController } from '../src/decorators.js';
 import { RpcKernel, RpcKernelConnection } from '../src/server/kernel.js';
 import { Session, SessionState } from '../src/server/security.js';
-import { BehaviorSubject } from 'rxjs';
+import { BehaviorSubject, Observable } from 'rxjs';
 import { getClassName, sleep } from '@deepkit/core';
 import { ProgressTracker } from '@deepkit/core-rxjs';
 
@@ -595,3 +595,20 @@ test('progress tracker reuse', async () => {
         expect(res).toBe(undefined);
     }
 });
+
+test('missing observable types throw', async () => {
+    class Controller {
+        @rpc.action()
+        test() {
+            return new Observable()
+        }
+    }
+
+    const kernel = new RpcKernel();
+    kernel.registerController(Controller, 'myController');
+    const client = new DirectClient(kernel);
+    const controller = client.controller<Controller>('myController');
+
+    const observable = await controller.test();
+    await expect(observable.toPromise()).rejects.toThrow('No observable type on RPC action detected.');
+});