DNS Records fails

I am running two node apps on one droplet, and using nginx. Yesterday I was setting two domains leading to two different ports on my droplet web server: www.domain.com - > http://localhost:9001 sub.domain.com - > http://localhost:9002

This is what I have done on nginx/sites-available/default to make it happen:

server { listen 80;

server_name domain.com www.domain.com;

location / {
    proxy_pass http://localhost:9001;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
}

}

server { listen 80;

server_name sub.domain.com;

location / {
    proxy_pass http://localhost:9003;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection 'upgrade';
    proxy_set_header Host $host;
    proxy_cache_bypass $http_upgrade;
}

}

It was working perfectly, but now I see that the nginx make the proxy pass only for the main domain, while it does nothing to the sub domain. (yes, both ports are working when accessing m.y.i.p:9002)

Also, I am getting this error on the Digital Ocean DNS log: dns_master_load: /dev/shm/bind/DO/db.grmmph.com:15: *.grmmph.com: CNAME and other data zone grmmph.com/IN: loading from master file /dev/shm/bind/DO/db.grmmph.com failed: CNAME and other data zone grmmph.com/IN: not loaded due to errors.

Any help? Please?