diff --git a/CHANGELOG.md b/CHANGELOG.md
index adaddb6..0cf30c7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to
 
 ### Added
 
+- ⚡️(fix) add error when mailbox create failed
 - ✨(mailbox) allow to reset password on mailboxes #834
 
 ## [1.16.0] - 2025-05-05
diff --git a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/api/useCreateMailbox.tsx b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/api/useCreateMailbox.tsx
index d9686db..cea8c0d 100644
--- a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/api/useCreateMailbox.tsx
+++ b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/api/useCreateMailbox.tsx
@@ -26,10 +26,13 @@ export const createMailbox = async ({
   });
 
   if (!response.ok) {
-    throw new APIError(
-      'Failed to create the mailbox',
-      await errorCauses(response),
-    );
+    const errorData = await errorCauses(response);
+    console.log('Error data:', errorData);
+    throw new APIError('Failed to create the mailbox', {
+      status: errorData.status,
+      cause: errorData.cause as string[],
+      data: errorData.data,
+    });
   }
 };
 
diff --git a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/MailBoxesView.tsx b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/MailBoxesView.tsx
index b3004fe..ada1e4f 100644
--- a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/MailBoxesView.tsx
+++ b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/MailBoxesView.tsx
@@ -127,7 +127,6 @@ export function MailBoxesView({ mailDomain }: { mailDomain: MailDomain }) {
                   <Button
                     data-testid="button-new-mailbox"
                     onClick={openModal}
-                    icon={<span className="material-icons">add</span>}
                     disabled={!isCreateMailboxFormVisible}
                   >
                     {t('New mail address')}
diff --git a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/ModalCreateMailbox.tsx b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/ModalCreateMailbox.tsx
index 79a5380..e6f32dc 100644
--- a/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/ModalCreateMailbox.tsx
+++ b/src/frontend/apps/desk/src/features/mail-domains/mailboxes/components/ModalCreateMailbox.tsx
@@ -66,7 +66,37 @@ export const ModalCreateMailbox = ({
       closeModal();
     },
     onError: (error) => {
-      const causes = parseAPIError({ error }) || [];
+      const causes =
+        parseAPIError({
+          error,
+          errorParams: [
+            [
+              ['Mailbox with this Local_part and Domain already exists'],
+              t('This email prefix is already used.'),
+              undefined,
+            ],
+            [
+              ['Invalid format'],
+              t('Invalid format for the email prefix.'),
+              undefined,
+            ],
+          ],
+          serverErrorParams: [
+            t(
+              'An error occurred while creating the mailbox. Please try again.',
+            ),
+            undefined,
+          ],
+        }) || [];
+      if (causes.length > 0) {
+        causes.forEach((cause) => {
+          toast(cause, VariantType.ERROR, { duration: 4000 });
+        });
+      } else {
+        toast(t('Mailbox create failed!'), VariantType.ERROR, {
+          duration: 4000,
+        });
+      }
       setErrorCauses(causes);
     },
   });