What is NGINX Expecting To See Here? - nginx-config

Question

I've been working on trying to integrate onlyoffice with my working nextcloud app. I've attempted this many times and in many different ways. I believe I understand "most" of the mistakes I've made previously...but there always seems to be one more.
Nextcloud is running on a Ubuntu 22.04 VM. I have another VM operating nginx reverse proxy for this and the other apps I want to expose to the outside. I've decided on this attempt to also run onlyoffice on the nextcloud server but using different ports from that app.
Using the modified template suggested for SSL enabled nginx, when I attempt to start the service, I get:
bonzo#cloud:/etc/nginx/conf.d$ systemctl status nginx.service
nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Fri 2022-08-05 15:12:02 CDT; 8s ago
Docs: man:nginx(8)
Process: 7990 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
CPU: 26ms
Aug 05 15:12:02 cloud systemd[1]: Starting A high performance web server and a reverse proxy
server...
Aug 05 15:12:02 cloud nginx[7990]: nginx: [emerg] host not found in upstream "docservice" in
/etc/nginx/includes/ds-docservice.conf:74
Aug 05 15:12:02 cloud nginx[7990]: nginx: configuration file /etc/nginx/nginx.conf test failed
Aug 05 15:12:02 cloud systemd[1]: nginx.service: Control process exited, code=exited,
status=1/FAILURE
Aug 05 15:12:02 cloud systemd[1]: nginx.service: Failed with result 'exit-code'.
Aug 05 15:12:02 cloud systemd[1]: Failed to start A high performance web server and a reverse
proxy server.*
When I looked at the line 74 in ds-docservice.conf, it shows this:
location / {
proxy_pass http://docservice;
}
And, I'm not exactly sure what it is expecting to see there. I haven't included it in this first post but I'd be happy to share my ds.conf or any other logs/configs that would be required for help with this. I also realize this is probably going to be something silly that I've missed or messed up, I'm still new to nginx and integrating onlyoffice has been a lot more difficult than you'd think, from the literature and yt vids I've seen!
Thanks for any help