Why doesn't a project launched via python runserver open in the browser?

Question

Django

Hello!
Suddenly, an incomprehensible problem arose: I
start the django project through python runserver I go
to the specified address in the browser, and the page does not open, that is, even an error message is not issued, it just says "Waiting for 127.0.0.1" , no information is displayed in the log.
This started to happen after reinstalling windows 10, first installed all the modules - launched - everything worked. Then suddenly this hang happened. That is, really unexpectedly, nothing was corrected in the code, no settings were changed.
Moreover, I can go to the admin panel, I can add objects, when I try to go to non-existent pages, information about 404 is displayed in the log. Another app, on 3.5 and django 1.10+ starts fine.
Tell me, with what in general it can be connected, in which direction to dig?
windows 10
python 2.7
django 1.7