Unable to load app 0 (mountpoint='') (callable not found or import error) - linux

Question

I have the below error with nginx uWSGI Flask application on CentOS 7 Linux:
unable to load app 0 (mountpoint='') (callable not found or import error)
I have followed Digital Ocean tut as my first time with Linux, after original Udemy tut using earlier Centos version didnt seem to work. I was able to get 'Hello world' type basic Python file to run on uwsgi and nginx following the tut, then I see several people have this error but seem different solutions. I changed permissions recursively on a parent folder above the app as I thought permissions might be source of error:
sudo chmod -R 771 www
and also giving nginx access to ?my user group? as Dig Ocean tutorial advised:
sudo usermod -a -G will nginx
chmod 710 /home/will
uwsgi.ini file is following, where /var/www/html/CON29Application1/Source/app.py is the app I want to run, not sure if module line is correct syntax:
[uwsgi]
module = Source.app
master = true
socket = /var/www/html/CON29Application1/socket.sock
chmod-socket = 777
vacuum = true
processes = 8
threads = 8
harakiri = 15
logto = /var/www/html/CON29Application1/log/%n.log
die-on-term = true
Systemd file is this at /etc/systemd/system/CON29Application1.service:
[Unit]
Description=uWSGI instance to serve CON29Application1
After=network.target
[Service]
User=will
Group=nginx
WorkingDirectory=/var/www/html/CON29Application1
Environment="PATH=/var/www/html/CON29Application1/venv/bin"
ExecStart=/var/www/html/CON29Application1/venv/bin/uwsgi --ini uwsgi.ini
[Install]
WantedBy=multi-user.target
This is default.conf file at /etc/nginx/conf.d/default.conf (server IP I blanked in this post for security reasons):
server {
listen 80;
server_name 188.xxx.xxx.xxx;
location / {
include uwsgi_params;
uwsgi_pass unix:/var/www/html/CON29Application1/socket.sock;
uwsgi_modifier1 30;
}
error_page 404 /404.html;
location = /404.html {
root /usr/share/nginx/html;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}
and this is app.py file:
from flask import Flask, render_template
...
app = Flask(__name__)
app.config.from_object('Source.config')
app.secret_key = "---------------------------------"
...
And sorry as I am not that sure which files are relevant to include, so here is also the full uwsgi.log file! Thanks for any ideas:
*** Starting uWSGI 2.0.15 (64bit) on [Wed Oct 4 13:26:19 2017] ***
compiled with version: 4.8.5 20150623 (Red Hat 4.8.5-16) on 02 October 2017 21:47:33
os: Linux-3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017
nodename: CON29Application1
machine: x86_64
clock source: unix
pcre jit disabled
detected number of CPU cores: 1
current working directory: /var/www/html/CON29Application1
detected binary path: /var/www/html/CON29Application1/venv/bin/uwsgi
your processes number limit is 1792
your memory page size is 4096 bytes
*** WARNING: you have enabled harakiri without post buffering. Slow upload could be rejected on post-unbuffered webservers ***
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
thunder lock: disabled (you can enable it with --thunder-lock)
uwsgi socket 0 bound to UNIX address /var/www/html/CON29Application1/socket.sock fd 3
Python version: 3.6.2 (default, Sep 27 2017, 16:30:17) [GCC 4.8.5 20150623 (Red Hat 4.8.5-16)]
Python main interpreter initialized at 0x9acbd0
python threads support enabled
your server socket listen backlog is limited to 100 connections
your mercy for graceful operations on workers is 60 seconds
mapped 1304064 bytes (1273 KB) for 64 cores
*** Operational MODE: preforking+threaded ***
unable to load app 0 (mountpoint='') (callable not found or import error)
*** no app loaded. going in full dynamic mode ***
*** uWSGI is running in multiple interpreter mode ***
spawned uWSGI master process (pid: 24254)
spawned uWSGI worker 1 (pid: 24259, cores: 8)
spawned uWSGI worker 2 (pid: 24260, cores: 8)
spawned uWSGI worker 3 (pid: 24261, cores: 8)
spawned uWSGI worker 4 (pid: 24262, cores: 8)
spawned uWSGI worker 5 (pid: 24263, cores: 8)
spawned uWSGI worker 6 (pid: 24264, cores: 8)
spawned uWSGI worker 7 (pid: 24265, cores: 8)
spawned uWSGI worker 8 (pid: 24266, cores: 8)