Apparently I cannot login

[sancho-s]

Using WWW-COURSERA-DOWNLOADER.ipynb, I apparently cannot login.
At cell after fter button_click('Log in') I get

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
~/.local/lib/python3.8/site-packages/splinter/element_list.py in __getitem__(self, index)
     41         try:
---> 42             return self._container[index]
     43         except IndexError:

IndexError: list index out of range

so I inserted

browser.visit('https://www.coursera.org/courses')
screenshot()

and the image shown

(cropped the bottom, irrelevant) is as if I were not logged in. I checked the username and password variables and they are ok.

What are possible causes and solutions?