diff --git a/db/models.py b/db/models.py
index 310e9fd..a3f0d7a 100644
--- a/db/models.py
+++ b/db/models.py
@@ -37,7 +37,9 @@ class User(BaseModel):
     mastodon_post_public = BooleanField(null=True, default=False)
 
     def mastodon_account(self):
-        if self.mastodon_server.name == MASTODON_INSTANCE:
+        if self.mastodon_server is None or self.mastodon_username is None:
+            return
+        elif self.mastodon_server.name == MASTODON_INSTANCE:
             return self.mastodon_username
         else:
             return f"{self.mastodon_username}@{self.mastodon_server}"
diff --git a/web/app.py b/web/app.py
index 630cb69..d388403 100644
--- a/web/app.py
+++ b/web/app.py
@@ -140,7 +140,7 @@ def mastodon_oauth():
 
   user_mastodon_user_set(current_user.db_user.id, username, access_token)
 
-  return redirect('/profile')
+  return redirect('/profile/')
 
 @app.route('/login')
 def login():
diff --git a/web/vite/src/Profile.tsx b/web/vite/src/Profile.tsx
index 6df6498..a0845f2 100644
--- a/web/vite/src/Profile.tsx
+++ b/web/vite/src/Profile.tsx
@@ -70,7 +70,10 @@ export const Profile: React.FC = () => {
   const [opened, { open, close }] = useDisclosure(false);
 
   const mastodon_account = React.useMemo(
-    () => `@${mastodon_username}@${mastodon_server}`,
+    () =>
+      mastodon_username && mastodon_server
+        ? `@${mastodon_username}@${mastodon_server}`
+        : null,
     [mastodon_server, mastodon_username],
   );