Handle all cases of login. Firstly refactor the code to move all the post login mechanisms to a function of its own. Then add support to redirect the user if the login was attempted from logout page. Finally if the post response we got contains html, it is not a valid JSON, which means the login failed. In this case catch the exception and show the login error.

[{"pk": 1, "model": "sites.site", "fields": {"domain": "example.com", "name": "example.com"}}, {"pk": 3, "model": "sites.site", "fields": {"domain": "fossee.in/pytask", "name": "PyTask "}}, {"pk": 2, "model": "sites.site", "fields": {"domain": "localhost:8080", "name": "Development Server"}}]