How I can cancel https?
After I log in, there is a message: "HTTPs (the encrypted version) of Todoist is only avaible for premium users".
And when I press "ok", "cancel" or "close" in it, page reload and this message became again.
How I can log in without https?
It is in Firefox 11.0. In Opera all is OK.
an HTTPS connection is indeed a Premium-only feature and any attempts of accessing Todoist via HTTPS with a free account, will force the application to reload and reconnect through HTTP. If you're still landing on the HTTPS page, please make sure you don't have any plugins installed in Firefox that try to always use HTTPS like "HTTPS Everywhere" for example.
It was it — HTTPS Everywhere.