Disclosure: I searched a lot, and I don\'t think my question (for my configuration) is answered here. For example run python script as cgi apache server doesn\'t answer it.
What could also cause these symptoms, is that you don't have the apache2 cgi module loaded. This will also generate a log message in /var/log/apache2/access.log
with an HTTP 304 error:
192.168.2.3 - - [26/Jul/2014:11:56:34 +0200] "GET /cgi-bin/hello.py HTTP/1.1" 304 179 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.125 Safari/537.36"
Check loaded modules with:
apache2ctl -M
Look for:
cgid_module (shared)
If it's not loaded, load it with:
a2enmod cgid
Then restart apache2:
service apache2 reload
Then refresh your browser and purge your browser cache (CTRL + F5). And/or restart your browser, to be sure it's requesting the actual page, instead of using the browser cache.