Hi, I've got the same problem.
That doesn't what driver is used and stuff.
The reason is very simple, by the time when you try to click the button which is span actually, it's not ready to be clicked due to complicated microsoft site logic.
Here is the solution, instead of clicking this button, submit the form that contains user_id and user password:
driver.FindElement(By.Id("cred_userid_inputtext")).SendKeys("name");
driver.FindElement(By.Id("cred_password_inputtext")).SendKeys("password");
driver.FindElement(By.Id("credentials")).Click();
Best, Boris.