fix: display error message when user or channel does not exists

back/api/channels.js

@@ -35,7 +35,7 @@ router.get('/:name', async (req, res) => {
     if (channel[0]) {
         res.send(channel[0]);
     } else {
-        res.send('No channel found');
+        res.status(400).send({ error: 'No channel found' });
     }
 });