This type of question is super hard to answer because the possibilities are almost endless. However, from what you're saying, if some machines CAN access the server and SOME can't, the problem is related to networking, and not the server software (or Django).
Though it could be related to either if you have some weird access rules setup that you're not mentioning in your response.
So, a few things to verify:
- Can the machines which cannot access the application via HTTP ping the server they reside on by its IP address? If they can't, you have a networking issue. Could be a routing problem, could be a firewall issue.
- To see if it's a routing problem, do a
traceroute
from one of the machines that cannot access your server, and see what happens. Did the traceroute stop at a particular router on your network? Well, then that's probably an issue.
- To see if it's a firewall issue, try changing the IP address of one of the machines that can't access the server to one of the machines who can. Did it work? OK, you have a firewall problem.