# Clear node_modules, re-install, and re-build the front-end assets
rm -rf node_modules && yarn install && yarn build
# Clear the Laravel cache
php artisan cache:clear
# Clear the Laravel config cache
php artisan config:clear
```
If you're still stuck, check below for a couple of common issues and their solutions.
## Common Issues
### You receive a `Class 'Pusher' not found` error
Solution: Add or set `BROADCAST_DRIVER=log` in your `.env` file. This will instruct Laravel to use `log` as the default broadcast driver instead.
### You receive an "Unknown error" when scanning using the web interface
Solution: Try scanning from the command line with php artisan koel:sync. Most of the time, you should receive a more detailed, easier to debug, message.
Refer to [Music Discovery](usage/music-discovery) for more details.
### You receive an `Integrity constraint violation: 1062 Duplicate entry for key 'artists_name_unique'` error when scanning
Solution: Set your database and table collation to utf8_unicode_ci.
### You receive an <input random strings here> error when running `yarn`
Solution: This most likely has little to do with Koel but more with your node/npm/yarn environment and installation. Deleting `node_modules` and rerunning the command sometimes help.
### Song stops playing, and you receive a `Failed to load resource: net::ERR_CONTENT_LENGTH_MISMATCH` error
Solution: This may sometimes happen with the native php streaming method. Check [Streaming Music](usage/streaming) for alternatives.
## Reinstalling Koel
In the worst case scenario, you can always reinstall Koel. Although Koel doesn't provide a built-in way to reinstall itself, you can do so manually by following these steps:
1. Backup your database
2. Have you backed up your database yet?
3. No seriously, make sure you have a backup of your database
4. Back up the `public/img` directory. This is where your album art, artist images, user avatars etc. are stored.
5. Delete or empty the root Koel directory
6. Follow the [installation guide](guide/getting-started#installation) to install Koel afresh
7. Restore your database and the `public/img` directory
By now you should have a fresh Koel installation with all your data intact and hopefully without the issue you were facing.
## Ask for Help
If you're still stuck, the [issue page](https://github.com/koel/koel/issues) on GitHub is a good place to ask for help. Remember to be civil and patient.
