diff --git a/api/controllers/InboxController.ts b/api/controllers/InboxController.ts
index ac2077c..09352f6 100644
--- a/api/controllers/InboxController.ts
+++ b/api/controllers/InboxController.ts
@@ -18,7 +18,7 @@ export async function createInbox({
     ? new mongoose.Types.ObjectId(domain_id)
     : undefined;
   inbox.name = name;
-  inbox.email = email || `${name.replace(/[^a-zA-Z0-9]/g, "-")}@${process.env.DEFAULT_EMAIL_DOMAIN}`;
+  inbox.email = email || await getNewRandomInboxEmail({ name });
   await inbox.save();
   return inbox;
 }
@@ -60,7 +60,8 @@ export async function getInboxByEmail(email: string) {
 }
 
 export async function getNewRandomInboxEmail({ name }: { name: string }) {
-  const email = `${name.replace(/[^a-zA-Z0-9]/g, "-")}-${Math.random()
+  const lowerCaseName = name.toLowerCase();
+  const email = `${lowerCaseName.replace(/[^a-zA-Z0-9]/g, "-")}-${Math.random()
     .toString(36)
     .substring(2, 12)}@${process.env.DEFAULT_EMAIL_DOMAIN}`;
   const inbox = await getInboxByEmail(email);
diff --git a/api/routes/v1/inboxes/index.ts b/api/routes/v1/inboxes/index.ts
index 48d9767..bcdbb6c 100644
--- a/api/routes/v1/inboxes/index.ts
+++ b/api/routes/v1/inboxes/index.ts
@@ -5,8 +5,10 @@ import { expressValidatorMiddleware } from "../../../middlewares/expressValidato
 import {
   createInbox,
   deleteInboxByOrganizationIdAndInboxId,
+  getInboxByEmail,
   getInboxByOrganizationIdAndInboxId,
   getInboxesByOrganizationId,
+  getNewRandomInboxEmail,
 } from "../../../controllers/InboxController";
 import { sendWebhookEvent } from "../../../controllers/WebhookAttemptController";
 import messagesRouter from "./messages";
@@ -40,7 +42,9 @@ router.post(
     res: Response
   ) => {
     let domainId: string | undefined;
+    let username: string | undefined;
     if (req.body.email) {
+      username = req.body.email?.split("@")[0];
       const domainName = req.body.email?.split("@")[1];
       if (!domainName) {
         return res.status(400).json({ error: "Invalid email address" });
@@ -49,18 +53,29 @@ router.post(
         organizationId: req.organization._id.toString(),
         name: domainName,
       });
-      if (!domain) {
-        return res.status(404).json({ error: "Domain not found" });
+
+      if (domain) {
+        domainId = domain._id.toString();
       }
+    }
 
-      domainId = domain._id.toString();
+    let email = undefined;
+    if (domainId) {
+      email = req.body.email;
+    } else if (username) {
+      const defaultEmail = `${username}@${process.env.DEFAULT_EMAIL_DOMAIN}`;
+      if (await getInboxByEmail(defaultEmail)) {
+        email = await getNewRandomInboxEmail({ name: username });
+      } else {
+        email = defaultEmail;
+      }
     }
 
     const inbox = await createInbox({
       organization_id: req.organization._id.toString(),
       name: req.body.name,
       domain_id: domainId,
-      email: domainId && req.body.email,
+      email,
     });
 
     await sendWebhookEvent({
diff --git a/app/app/pages/login.vue b/app/app/pages/login.vue
index 7eec48a..446643f 100644
--- a/app/app/pages/login.vue
+++ b/app/app/pages/login.vue
@@ -42,7 +42,7 @@
 
     <p class="auth-footer">
       New to Sendook?
-      <NuxtLink to="https://app.sendook.com/signup">Create an account</NuxtLink>
+      <NuxtLink to="/signup">Create an account</NuxtLink>
     </p>
   </div>
 </template>