Most of issue come from DDos Attack, DDoS Attack can make your website get overloaded/flooded with high traffic and took lot of resources.
Mostly you get one of this errors:
- 503 Service Unavailable Error
- 502 Bad Gateway Error
- 500 Internal Server Error
To protect your website you can use CloudFlare as DDoS Protection.
My product don’t contain any DDoS Protection, if your website got attacked its your problem, ask your web hosting provider or migrate to web hosting that offer DDoS Protection.