It feels like GCP is wiping the node modules? O_o?
Do you have other projects running in pm2 ? If not, then run this please:
pm2 delete all
NODE_ENV=production pm2 start npm --name="exerche_server" -- run start
pm2 logs and share here the output.
I was working with @Saad_Mujeeb via Anydesk to remote in and check his server. It appears google doesn’t install sendmail (apt package) by default in their images, even after installing that and configuring it, the connection isn’t happening.
I think the node_modules thing was just a side error, for whatever reason Strapi is trying to contact the local sendmail package and it’s just timing out. Strapi sits there waiting and Nginx doesn’t get a response.
I plan on doing some testing on GCP, but for the moment I’ve recommended he try using one of the third party providers for email and configure it via the plugins.js file.
EDIT: also GCP blocks outbound port 25 regardless of firewall rules: Sending email from an instance | Compute Engine Documentation