Fixing Errors "Connection to upstream refused/skipped"

The Connection to upstream refused and Connection to upstream skipped errors indicate a problem when the application was started. This may be either the HTTP server that cannot be started or the application that starts but is not listing to the correct IP. Regardless of the reason, more information is available from the $HOME/admin/logs/sites logs.

Here is a non-exhaustive list of examples:

Apache

Disk quota exceeded

=> Site log for a site using Apache:
STDERR: (122)Disk quota exceeded: apache: could not open error log file /home/foo/admin/logs/apache/apache.log.

=> Logs Apache ($HOME/admin/logs/apache):
[error] (122)Disk quota exceeded: Couldn't bind unix domain socket /home/foo/admin/config/apache/run/cgisoc
k.XXXXXXX
[error] (122)Disk quota exceeded: could not create /home/foo/admin/config/apache/run/apache.pid
[error] apache: could not log pid to file /home/foo/admin/config/apache/run/apache.pid

Choose the next higher pack from the Accounts tab in your administration interface or delete files. This especially affects free 100 Mb packs.

Cannot find Apache log

STDERR: (2)No such file or directory: apache: could not open error log file /home/foo/admin/logs/apache/apache.log.
STDERR: Unable to open logs

Try and restart the Apache instance (Web > Sites > Restart a PHP type site) to regenerate it or perform a notable change to one of the affected sites (e.g. by adding a fictitious address).

Spurious characters

STDERR: Syntax error on line XXX of /home/foo/admin/config/apache/sites.conf:
STDERR: Invalid command 'XXX', perhaps misspelled or defined by a module not included in the server configuration

Spurious characters or directives that do not use the correct syntax have been added to the Global directives field for a custom Apache type site at the virtual host field level for the relevant site or at the Apache configuration level (Web > Configuration > Apache).

Correct them or delete them.

uWSGI

=> Logs sites :
STDERR: [uWSGI] getting INI configuration from /home/foo/admin/config/uwsgi/XXXXX.conf
Upstream starting failed: /usr/alwaysdata/uwsgi/2.0.17.1/bin/uwsgi --ini /home/foo/admin/config/uwsgi/XXXXX.conf (return code: 1 | reason: -)

=> Logs uWSGI ($HOME/admin/logs/uwsgi) :
chdir() to /home/foowww
chdir(): No such file or directory [core/uwsgi.c line 2631]
-----
failed to open python file /home/foo/www/app.py
unable to load app 0 (mountpoint='') (callable not found or import error)
-----
unable to find "application" callable in file /home/foo/www/manage.py
-----
ModuleNotFoundError: No module named 'XXXX'

Depending on the error, correct the site, the virtual environment or the script itself.

For instance, for a Python application (such as Django), check that the version in your virtual environment matches the version declared in your site (in the admin interface).

Other HTTP servers

For sites that do not use Apache or uWSGI, check the program run in SSH. Especially whether it does properly listen on:

• IPv6,
• on IP and the set port.

Upstream not ready

Upstream starting failed: node ~/www/app.js (return code: - | reason: No such file or directory: '/www/')

The working directory specified in Web > Sites does not exist.

Incorrect command (path)

STDERR: internal/modules/cjs/loader.js:589
STDERR:     throw err;
STDERR:     ^
STDERR: 
STDERR: Error: Cannot find module '/home/foo/www/app.js'
STDERR:     at Function.Module._resolveFilename (internal/modules/cjs/loader.js:587:15)
STDERR:     at Function.Module._load (internal/modules/cjs/loader.js:513:25)
STDERR:     at Function.Module.runMain (internal/modules/cjs/loader.js:760:12)
STDERR:     at startup (internal/bootstrap/node.js:308:19)
STDERR:     at bootstrapNodeJSCore (internal/bootstrap/node.js:878:3)
Upstream starting failed: node ~/www/app.js

The /home/foo/www/app.js file does not exist.

Cannot parse upstream response

This error means that an HTTP response returned by your server/application is incorrect (badly formulated) and therefore that our proxy cannot parse it (and return it).