Express won't serve Client on Droplet

Hello, I’m at my wits end so here we go.

I created a working MERN stack app on DO a couple months ago (APP1), it works fantastically. I decided to use that app as a code base for another MERN app (APP2). Nearly nothing has changed from APP1 to APP2. The only changes have been to strings for the sake of renaming. APP2 works wonderfully in development environments, but won’t even present me with a “Cannot GET” message when I deploy it to a droplet. The droplet is reachable via ping, so I know it’s active. I get no errors during deployment. I don’t have the client setup to use a proxy. I do not have any dependency differences between APP1 and APP2. The only thing I have to go on is the error message in my browsers: “This site can’t be reached. xxx.xxx.xxx.xxx Refused to connect”.

I’m happy to provide any additional information or run suggested tests. Thank you for your time.