Rails/Nginx/Passenger ERROR: Phusion Passenger doesn't seem to be running - ruby-on-rails

Question

I was setting up Passenger and Nginx for my Rails App (Mac OS X 10.11).
I used these commands:
gem install passenger
rvmsudo passenger-install-nginx-module
All these gets installed perfectly.
Added nginx path in .bash_profile:
export PATH=$PATH:/opt/nginx/sbin/
My nginx conf:
passenger_root /Users/MyUserName/.rvm/gems/ruby-2.2.5#rails4115/gems/passenger-5.3.4;
passenger_ruby /Users/MyUserName/.rvm/gems/ruby-2.2.5#rails4115/wrappers/ruby;
server {
listen 443;
ssl on;
server_name app1-local.staging.com;
rails_env development;
passenger_enabled on;
root /Users/MyUsername/Desktop/Github/MainApp/public;
ssl_certificate /opt/nginx/ssl/mainapp.com.crt;
ssl_certificate_key /opt/nginx/ssl/mainapp.com.key;
}
server {
listen 443;
ssl on;
server_name app2-local.staging.com app3-local.staging.com app4-local.staging.com local.staging.com;
rails_env development;
passenger_enabled on;
root /Users/MyUsername/Desktop/Github/MainApp2/public;
ssl_certificate /opt/nginx/ssl/mainapp.com.crt;
ssl_certificate_key /opt/nginx/ssl/mainapp.com.key;
}
server {
listen 80;
server_name app1-local.staging.com;
rails_env development;
passenger_enabled on;
root /Users/MyUsername/Desktop/Github/MainApp/public;
}
server {
listen 80;
server_name app2-local.staging.com app3-local.staging.com app4-local.staging.com local.staging.com;
rails_env development;
passenger_enabled on;
root /Users/MyUsername/Desktop/Github/MainApp2/public;
}
After this I started nginx: sudo nginx, it worked. Now if I visit local.staging.com, I get 502 internal server error.
Nginx error logs displays:
upstream prematurely closed connection while reading response header from upstream
If I do passenger-status, it outputs:
Phusion Passenger is currently not serving any applications.
Note: on running, passenger-config validate-install command, it says Everything looks good. :-)
EDIT
Output of sudo passenger-memory-stats:
-------- Apache processes --------
----------- Nginx processes ------------
PID PPID VMSize Resident Name
62366 1 2411.6 MB 1.3 MB nginx: master process nginx
63016 62366 2411.6 MB 1.5 MB nginx: worker process
63008 28339 2377.8 MB 0.3 MB tail -f /opt/nginx/logs/error.log
------ Passenger processes ------
PID VMSize Resident Name
36415 0.0 MB 0.0 MB (PassengerAgent)
63010 2416.8 MB 3.3 MB Passenger watchdog
63014 2417.6 MB 3.3 MB Passenger ust-router
63602 2457.3 MB 5.7 MB Passenger core
EDIT 2
Now in nginx error.log, getting:
Process aborted! signo=SIGSEGV(11), reason=#0, signal sent by PID 0 with UID 0, si_addr=0x0, randomSeed=1534502322
And
upstream prematurely closed connection while reading response header from upstream
Any help here?