I updated the Nginx config on App service(linux), it suddenly not working. What should be the possible reason

Question

I have a App service (Linux) with a Laravel application. I updated the Nginx config in order to fulfill the Laravel needs with SSH. It keeps working fine. Yesterday the website suddenly not working. I find out it's the issue of nginx config. I reload the nginx config then it works again. No one can access the Azure portal so there should be no possibility that someone restart or change the server. Also I checked that's no activity or deployment log.

May I know is that any reason for the issue above. Is it a good practice to change the Nginx config with SSH? I also included a replace and reload script on the start script to make sure the Nginx config should be updated even any restart or deployment. This script is also working fine.