Getting Unusual Error while using Selenium and PhantomJS in Python

I'm trying to fill the forms of these page, I checked the HTML code and the forms that I'm looking for are there but when I run my code, I got an error that I never seen in selenium.

I'm using PhantomJS 2.1.1 in Python 3.6.1 with Selenium.

I Want to fill these form.

<input type="text" name="Dt_Ref" value="31/08/2017" maxlength="10" size="10" class="form_data" onBlur="formatCamp(this, 'date');javascript:if(REUNE.Dt_Ref.value!=REUNE.Dt_RefAnt.value){REUNE.target='_self';REUNE.action='reune.asp';REUNE.submit()};" onKeyPress="return(validaConteudo(event, this, 'date'))" onKeyUp="saltaCampo(event, this, 'date',8)" onFocus="removeCaracs(this, 'date')">  <a style="cursor:hand; cursor:pointer;" onclick="openCalendar(document.REUNE.elements['Dt_Ref']);return false;">

My Code is:

from selenium import webdriver


url = 'http://www.anbima.com.br/reune/reune.asp'
path_phantom = 'C:\\Users\\TBMEPYG\\AppData\\Local\\Continuum\\Anaconda3\\Lib\\site-packages\\phantomjs-2.1.1-windows\\bin\\phantomjs.exe'

#Processing

driver = webdriver.PhantomJS(executable_path= path_phantom)
driver.get(url)
name = driver.find_element_by_name("Dt_Ref")
driver.quit()

And I got this error:

Traceback (most recent call last):
  File "C:\Users\TBMEPYG\Desktop\beta_anbima.py", line 11, in <module>
    name = driver.find_element_by_name("Dt_Ref")
  File "C:\Users\TBMEPYG\AppData\Local\Continuum\Anaconda3\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 426, in find_element_by_name
    return self.find_element(by=By.NAME, value=name)
  File "C:\Users\TBMEPYG\AppData\Local\Continuum\Anaconda3\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 832, in find_element
    'value': value})['value']
  File "C:\Users\TBMEPYG\AppData\Local\Continuum\Anaconda3\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 297, in execute
    self.error_handler.check_response(response)
  File "C:\Users\TBMEPYG\AppData\Local\Continuum\Anaconda3\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 194, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: {"request":{"headers":{"Accept":"application/json","Accept-Encoding":"identity","Connection":"close","Content-Length":"89","Content-Type":"application/json;charset=UTF-8","Host":"127.0.0.1:64945","User-Agent":"Python http auth"},"httpVersion":"1.1","method":"POST","post":"{\"using\": \"name\", \"value\": \"Dt_Ref\", \"sessionId\": \"cc170460-8e5e-11e7-ad22-8d3d940cf70e\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/cc170460-8e5e-11e7-ad22-8d3d940cf70e/element"}}
Screenshot: available via screen

This is the first step of my code. I'm under a bank proxy and this could be the problem. When I access from my Chrome, the page works fine. When I try to use the same code (changing the url and the element name) in this site, it works fine.

Thank you all.