After replacing my find_element_by_*() function calls with find_element(by=By.*), my automated login stopped working. Any ideas why?

Question

Basically, I am trying to login to a website using a Selenium WebDriver. Based on the deprecation warnings I was getting when running my code, I changed the function calls.

From:

# Old login code
username = 'username'
password = 'password'

driver.find_element_by_id("u").send_keys(username)
driver.find_element_by_id("p").send_keys(password)

button = driver.find_element_by_xpath("//button[text()='Login']")
button.click()

To:

# New login code
username = 'username'
password = 'password'

driver.find_element(by=By.ID, value='u').send_keys(username)
driver.find_element(by=By.ID, value='p').send_keys(username)

button = driver.find_element(by=By.XPATH, value="//button[text()='Login']")
button.click()

Now, my selenium web driver fails to login at the very same link. Does anyone know what is going on? Things I should check for? I understand this issue might be specific to the website I am trying to login to.

For now, I'm just planning to keep the old code, but would love to get this fixed.