Nginx only responding to 1 of multiple https servers - nginx

Question

The problem I'm facing is that I have nginx configured for 2 HTTPS servers and 1 is responding and working correctly but the other one with a near identical server config is showing "connection refused".
System:
Description: Ubuntu 22.04 LTS
nginx version: nginx/1.18.0 (Ubuntu)
I am working with a default nginx.conf file and have unlinked the default sites-available entry and each server_name is a subdomain with its own SSL cert & key. When I check the access and error logs there are no entries describing why subdomain2 connection is refused, or even log entries showing a connection attempt was made. Both cert/key pairs were generated by the IT dept at a university and since 1 is working fine I have good reason to think both pairs are valid.
I'm no nginx expert but I've setup multiple subdomains like this on different systems with success and am not sure what's going on. I've double & triple checked the basic stuff like making sure a valid sym-link exists in sites-enabled, no errors show up on nginx restart or systemctl status, and obviously the machine itself is listening on 0.0.0.0:https per netstat output as well as subdomain1 working correctly. I've also verified that the proxy_pass destination works when I use subdomain1 to point to it (also verified with curl on the nginx host).
Let me know if there is any other information I can provide.
Any help is appreciated.
Thanks
/etc/nginx/sites-available/subdomain1:
server {
listen 443 ssl;
server_name subdomain1.base.edu;
ssl_certificate /path/server.crt;
ssl_certificate_key /path/server.key;
client_max_body_size 0;
add_header Strict-Transport-Security max-age=15768000;
location / {
proxy_pass http://127.0.0.1:8000;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_set_header X-Scheme $scheme;
proxy_buffering off;
}
}
/etc/nginx/sites-available/subdomain2:
server {
listen 443 ssl;
server_name subdomain2.base.edu;
ssl_certificate /path/server.crt;
ssl_certificate_key /path/server.key;
location / {
proxy_pass http://127.0.0.1:10123;
}
}
UPDATE (nginx -T output)
user#host:/etc/nginx/sites-available$ sudo nginx -T
[sudo] password:
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
.....
# configuration file /etc/nginx/sites-enabled/subdomain1.base.edu:
# top-level http config for websocket headers
# If Upgrade is defined, Connection = upgrade
# If Upgrade is empty, Connection = close
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
server {
listen 80;
server_name subdomain1.base.edu;
return 302 https://$host$request_uri;
}
server {
listen 443 ssl;
server_name subdomain1.base.edu;
ssl_certificate /path/.ssl/server.crt;
ssl_certificate_key /path/.ssl/server.key;
client_max_body_size 0;
add_header Strict-Transport-Security max-age=15768000;
include /etc/nginx/sites-available/shinyapps;
location / {
proxy_pass http://127.0.0.1:8000;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# websocket headers
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_set_header X-Scheme $scheme;
proxy_buffering off;
}
}
# configuration file /etc/nginx/sites-available/shinyapps:
location /5627 {
proxy_pass http://localhost:5627/;
proxy_redirect / $scheme://$http_host/;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_read_timeout 20d;
proxy_buffering off;
}
# configuration file /etc/nginx/sites-enabled/subdomain2.base.edu:
#
# bustalab1 domain to proxy localhost shiny apps
server {
listen 80;
server_name subdomain2.base.edu;
# Tell all requests to port 80 to be 302 redirected to HTTPS
return 302 https://$host$request_uri;
}
server {
listen 443 ssl;
server_name subdomain2.base.edu;
ssl_certificate /path/.ssl/subdomain2.crt;
ssl_certificate_key /path/.ssl/subdomain2.key;
error_log /var/log/nginx/subdomain2_err.log debug;
access_log /var/log/nginx/subdomain2_acc.log;
location / {
proxy_pass http://127.0.0.1:10123;
}
}