Laradock (docker) keeps throwing http error 500
A potential problem I see is that you use IP addresses for your service hosts (DB_HOST, REDIS_HOST) in your .env. Potentially these IP addresses can change and it is therefore safer to use the container names as host address. In your case youll want to use "DB_HOST=mysql" and "REDIS_HOST=redis".
The http 500 means there is probably nothing wrong with your nginx config and sounds more like a Laravel configuration problem. I suggest you inspect your laravel log file (storage/logs/laravel.log) for more information.