Ok, long shot here. I'm doing a POC using a headless browser (Seleium/PhantomJS (C#)) and it is kicking my tail. Sometimes things work and then they don't. My login code is something like:

private IWebDriver _driver = new PhantomJSDriver();
_driver.Navigate().GoToUrl(LoginURL);
_driver.FindElement(By.Name("txtUser")).SendKeys(UserName);
_driver.FindElement(By.Name("txtPass")).SendKeys(Password);
_driver.FindElement(By.TagName("button")).Click();

and it doesn't find it even though it in in _driver.PageSource.

All the SO stuff is from 2013 and I’ve tried many, many, four days worth of many By.XPath, By.Id, By.Name combinations and it just doesn’t work.