That would appear to be a problem with your nginx or digitalocean configuration rather than a node-red problem so this might not be the best place to ask.
I am not exactly sure to be honest. I have tried everything that has been suggested. The entire deloyment is for running Node-Red and that is the one thing that is not working. When someone suggested I bring this to a Node-Red forum, I joined here and hoping someone could give me some direction.
@hardillb has recently published details and simple setup for running 1 (or many) node-red instances under FlowForge in a digitalocean droplet
You can find the FlowForge entry in the Digital Ocean Marketplace here. You will need a domain to host the FlowForge app and any projects you end up running.
It will run in the $6 a month Droplet size, but you may want to bump it to to one of the large offerings depending on how many projects you want to end up running.
I watched Ben do a demo and took him less than 10 mins to have a fully working node-red.
I am already using FlowForge and its great. I am on a $15 per month plan and every now and again I get a warning saying payload is too big. I guess then want me to pay more for the next level up ($50 per month).