I can’t access the admin panel links as I click it shows 403 error

You might just need to flush permalinks. (Navigate to Settings > Permalinks and click “Save Changes”) If you can’t navigate to the permalinks page because of the error, you could try one of the other suggestions here

Obviously make a backup of your database before performing any of them.

If that doesn’t work there may be a permissions issue. It’s generally suggested that the folders be set to 755 and files to 644. You can read more about WP file permissions here