v2ray service failed to start under certbot ssl certs

Failed to build TLS config, config.json (code=exited, status=1/FAILURE)

Use journalctl -u v2ray to check failure detail

In this case, ssl certificates generated by certbot are readable only by the user root (0), and v2ray service runs under the user nobody; hence v2ray service fails to initiate.

Edit /etc/systemd/system/v2ray.service by changing User=nobody to User=root will allow the service to start. A more appropriate solution would be to define a new user in the group ssl-cert and follow https://sigmaris.info/blog/2019/01/make-certbot-lets-encrypt-certificates-readable-by-debian-ssl-cert-group/ to configure certbot and finally use this user to run v2ray service.