diff --git a/addons/web/static/src/core/errors/error_handlers.js b/addons/web/static/src/core/errors/error_handlers.js
index f0d63de995c..3a35daec50a 100644
--- a/addons/web/static/src/core/errors/error_handlers.js
+++ b/addons/web/static/src/core/errors/error_handlers.js
@@ -97,6 +97,12 @@ export function rpcErrorHandler(env, error, originalError) {
                 ErrorComponent = errorDialogRegistry.get(exceptionName);
             }
         }
+        if (!ErrorComponent && originalError.data.context) {
+            const exceptionClass = originalError.data.context.exception_class;
+            if (errorDialogRegistry.contains(exceptionClass)) {
+                ErrorComponent = errorDialogRegistry.get(exceptionClass);
+            }
+        }
 
         env.services.dialog.add(ErrorComponent || RPCErrorDialog, {
             traceback: error.traceback,
diff --git a/addons/web/static/src/core/network/rpc_service.js b/addons/web/static/src/core/network/rpc_service.js
index 9ab20fc4f72..a7fbceef2d5 100644
--- a/addons/web/static/src/core/network/rpc_service.js
+++ b/addons/web/static/src/core/network/rpc_service.js
@@ -29,11 +29,8 @@ export function makeErrorFromResponse(reponse) {
     // Odoo returns error like this, in a error field instead of properly
     // using http error codes...
     const { code, data: errorData, message, type: subType } = reponse;
-    const { context: data_context, name: data_name } = errorData || {};
-    const { exception_class } = data_context || {};
-    const exception_class_name = exception_class || data_name;
     const error = new RPCError();
-    error.exceptionName = exception_class_name;
+    error.exceptionName = errorData.name;
     error.subType = subType;
     error.data = errorData;
     error.message = message;
diff --git a/addons/web/static/tests/core/errors/error_service_tests.js b/addons/web/static/tests/core/errors/error_service_tests.js
index a0636dd2dc6..2b9d10c59e5 100644
--- a/addons/web/static/tests/core/errors/error_service_tests.js
+++ b/addons/web/static/tests/core/errors/error_service_tests.js
@@ -80,7 +80,7 @@ QUnit.test("handle RPC_ERROR of type='server' and no associated dialog class", a
 });
 
 QUnit.test(
-    "handle RPC_ERROR of type='server' and associated custom dialog class",
+    "handle custom RPC_ERROR of type='server' and associated custom dialog class",
     async (assert) => {
         assert.expect(2);
         class CustomDialog extends Component {}
@@ -89,17 +89,21 @@ QUnit.test(
         const error = new RPCError();
         error.code = 701;
         error.message = "Some strange error occured";
-        error.exceptionName = "strange_error";
+        const errorData = {
+            context: { exception_class: "strange_error" },
+            name: "strange_error",
+        };
+        error.data = errorData;
         function addDialog(dialogClass, props) {
             assert.strictEqual(dialogClass, CustomDialog);
             assert.deepEqual(props, {
                 name: "RPC_ERROR",
                 type: "server",
                 code: 701,
-                data: null,
+                data: errorData,
                 subType: null,
                 message: "Some strange error occured",
-                exceptionName: "strange_error",
+                exceptionName: null,
                 traceback: error.stack,
             });
         }
@@ -111,6 +115,46 @@ QUnit.test(
     }
 );
 
+QUnit.test(
+    "handle normal RPC_ERROR of type='server' and associated custom dialog class",
+    async (assert) => {
+        assert.expect(2);
+        class CustomDialog extends Component {}
+        CustomDialog.template = tags.xml`<RPCErrorDialog title="'Strange Error'"/>`;
+        CustomDialog.components = { RPCErrorDialog };
+        class NormalDialog extends Component {}
+        NormalDialog.template = tags.xml`<RPCErrorDialog title="'Normal Error'"/>`;
+        NormalDialog.components = { RPCErrorDialog };
+        const error = new RPCError();
+        error.code = 701;
+        error.message = "A normal error occured";
+        const errorData = {
+            context: { exception_class: "strange_error" },
+        };
+        error.exceptionName = "normal_error";
+        error.data = errorData;
+        function addDialog(dialogClass, props) {
+            assert.strictEqual(dialogClass, NormalDialog);
+            assert.deepEqual(props, {
+                name: "RPC_ERROR",
+                type: "server",
+                code: 701,
+                data: errorData,
+                subType: null,
+                message: "A normal error occured",
+                exceptionName: "normal_error",
+                traceback: error.stack,
+            });
+        }
+        serviceRegistry.add("dialog", makeFakeDialogService(addDialog), { force: true });
+        await makeTestEnv();
+        errorDialogRegistry.add("strange_error", CustomDialog);
+        errorDialogRegistry.add("normal_error", NormalDialog);
+        const errorEvent = new PromiseRejectionEvent("error", { reason: error, promise: null });
+        await unhandledRejectionCb(errorEvent);
+    }
+);
+
 QUnit.test("handle CONNECTION_LOST_ERROR", async (assert) => {
     patchWithCleanup(browser, {
         setTimeout: (callback, delay) => {