diff --git a/addons/mail/controllers/discuss/channel.py b/addons/mail/controllers/discuss/channel.py
index 83bb5099e2f..4cf6d3b34b0 100644
--- a/addons/mail/controllers/discuss/channel.py
+++ b/addons/mail/controllers/discuss/channel.py
@@ -28,7 +28,10 @@ class ChannelController(http.Controller):
     @http.route("/discuss/channel/info", methods=["POST"], type="json", auth="public")
     @add_guest_to_context
     def discuss_channel_info(self, channel_id):
-        return request.env["discuss.channel"].search([("id", "=", channel_id)])._channel_info()
+        channel = request.env["discuss.channel"].search([("id", "=", channel_id)])
+        if not channel:
+            return
+        return channel._channel_info()[0]
 
     @http.route("/discuss/channel/messages", methods=["POST"], type="json", auth="public")
     @add_guest_to_context
diff --git a/addons/mail/static/src/core/common/thread_service.js b/addons/mail/static/src/core/common/thread_service.js
index 7eb371c93cc..8cf6145b55a 100644
--- a/addons/mail/static/src/core/common/thread_service.js
+++ b/addons/mail/static/src/core/common/thread_service.js
@@ -44,10 +44,13 @@ export class ThreadService {
     /**
      * @param {import("models).Thread} thread
      * @param {number} id
-     * @returns {Promise<import("models").Thread>}
+     * @returns {Promise<import("models").Thread|undefined>}
      */
     async fetchChannel(id) {
-        const [channelData] = await this.rpc("/discuss/channel/info", { channel_id: id });
+        const channelData = await this.rpc("/discuss/channel/info", { channel_id: id });
+        if (!channelData) {
+            return;
+        }
         return this.store.Thread.insert({
             ...channelData,
             model: "discuss.channel",
diff --git a/addons/mail/static/src/core/web/discuss_client_action.js b/addons/mail/static/src/core/web/discuss_client_action.js
index b4263ac1c49..16cdb6e6302 100644
--- a/addons/mail/static/src/core/web/discuss_client_action.js
+++ b/addons/mail/static/src/core/web/discuss_client_action.js
@@ -58,6 +58,9 @@ export class DiscussClientAction extends Component {
             const thread =
                 this.store.Thread.get({ model, id }) ??
                 (await this.threadService.fetchChannel(parseInt(id)));
+            if (!thread) {
+                return;
+            }
             if (!thread.is_pinned) {
                 await this.threadService.pin(thread);
             }
diff --git a/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js b/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js
index 85294ae4ca6..f3e7850b07b 100644
--- a/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js
+++ b/addons/mail/static/src/discuss/core/common/discuss_core_common_service.js
@@ -233,12 +233,10 @@ export class DiscussCoreCommon {
         const { id, message: messageData } = notif.payload;
         let channel = this.store.Thread.get({ model: "discuss.channel", id });
         if (!channel || !channel.type) {
-            const [channelData] = await this.rpc("/discuss/channel/info", { channel_id: id });
-            channel = this.store.Thread.insert({
-                model: "discuss.channel",
-                type: channelData.channel_type,
-                ...channelData,
-            });
+            channel = await this.threadService.fetchChannel(id);
+            if (!channel) {
+                return;
+            }
         }
         if (!channel.is_pinned) {
             this.threadService.pin(channel);
diff --git a/addons/mail/static/tests/discuss/core/web/discuss_tests.js b/addons/mail/static/tests/discuss/core/web/discuss_tests.js
index 571da2ea63a..857ff05c9f6 100644
--- a/addons/mail/static/tests/discuss/core/web/discuss_tests.js
+++ b/addons/mail/static/tests/discuss/core/web/discuss_tests.js
@@ -193,3 +193,10 @@ QUnit.test("Chat is added to discuss on other tab that the one that joined", asy
     await contains(".o-mail-DiscussSidebarChannel", { target: tab1.target, text: "Jerry Golay" });
     await contains(".o-mail-DiscussSidebarChannel", { target: tab2.target, text: "Jerry Golay" });
 });
+
+QUnit.test("no conversation selected when opening non-existing channel in discuss", async () => {
+    await startServer();
+    const { openDiscuss } = await start();
+    await openDiscuss(200); // non-existing id
+    await contains("h4", { text: "No conversation selected." });
+});
diff --git a/addons/mail/static/tests/helpers/mock_server/models/discuss_channel.js b/addons/mail/static/tests/helpers/mock_server/models/discuss_channel.js
index afcff843c6a..5b91aeb723b 100644
--- a/addons/mail/static/tests/helpers/mock_server/models/discuss_channel.js
+++ b/addons/mail/static/tests/helpers/mock_server/models/discuss_channel.js
@@ -89,7 +89,7 @@ patch(MockServer.prototype, {
         }
         if (route === "/discuss/channel/info") {
             const id = args.channel_id;
-            return this._mockDiscussChannelChannelInfo([id]);
+            return this._mockDiscussChannelChannelInfo([id])[0];
         }
         if (args.model === "discuss.channel" && args.method === "add_members") {
             const ids = args.args[0];
diff --git a/addons/mail/static/tests/helpers/test_utils.js b/addons/mail/static/tests/helpers/test_utils.js
index 14d87216347..e3e0dc9ad99 100644
--- a/addons/mail/static/tests/helpers/test_utils.js
+++ b/addons/mail/static/tests/helpers/test_utils.js
@@ -34,27 +34,13 @@ registryNamesToCloneWithCleanup.push("mock_server_callbacks", "discuss.model");
 function getOpenDiscuss(webClient, { context = {}, params = {}, ...props } = {}) {
     return async function openDiscuss(pActiveId) {
         const actionOpenDiscuss = {
+            context: { ...context, active_id: pActiveId },
             // hardcoded actionId, required for discuss_container props validation.
             id: 104,
-            context,
             params,
             tag: "mail.action_discuss",
             type: "ir.actions.client",
         };
-        const activeId =
-            pActiveId ?? context.active_id ?? params.default_active_id ?? "mail.box_inbox";
-        let [threadModel, threadId] =
-            typeof activeId === "number" ? ["discuss.channel", activeId] : activeId.split("_");
-        if (threadModel === "discuss.channel") {
-            threadId = parseInt(threadId, 10);
-        }
-        // TODO-DISCUSS-REFACTORING: remove when activeId will be handled.
-        webClient.env.services["mail.thread"].setDiscussThread(
-            webClient.env.services["mail.store"].Thread.insert({
-                model: threadModel,
-                id: threadId,
-            })
-        );
         await doAction(webClient, actionOpenDiscuss, { props });
     };
 }