diff --git a/dashboard/src/components/app/Email.vue b/dashboard/src/components/app/Email.vue
index c517c472c..067a29807 100644
--- a/dashboard/src/components/app/Email.vue
+++ b/dashboard/src/components/app/Email.vue
@@ -145,7 +145,7 @@ onMounted(async () => {
                   <TextInput v-if="sendmailSupportsDisplayName" v-model="sendmailDisplayName" :placeholder="$t('app.email.from.displayName')"/>
                   <TextInput v-model="sendmailMailboxName" :placeholder="$t('app.email.from.mailboxPlaceholder')"/>
                   <label>@</label>
-                  <SingleSelect v-model="sendmailDomain" :options="domains" option-key="id"/>
+                  <SingleSelect v-model="sendmailDomain" :disabled="!enableMailbox" :options="domains" option-key="id"/>
                 </InputGroup>
               </FormGroup>
             </fieldset>