Problem with selenium in python

I made a program to download 64 invoices, it goes well until the ninth, but when it arrives in it selenium stops clicking without error

All elif get a different id and perform the same action with it, but when it arrives at the ninth elif it hangs, but if I start straight from 9 it works and hangs at 17, I would like to know why it hangs from 9 to 9

It stops at this snippet of code:

segunda_via = driver.find_element_by_xpath('//*[@class="card-vertical-align ng-scope"]')
    segunda_via.click()
    #sleep(10)

and this is the rest of the code, having 63 elif between the first if and the else, locking only at ninth:

while a < 64:         #Mode chrome driver options         chrome_options = Options ()         # location of donwloads         download_dir="C: \ scrapy"

    #Novas configurações
    chrome_options.add_experimental_option('prefs', {
        "plugins.plugins_list": [{"enabled":False,"name":"Chrome PDF Viewer"}],
        "download": {
        "prompt_for_download": False,
        "default_directory"  : download_dir
        }
    })
    #Localizar webdriver no pc e entrar no site
    driver = webdriver.Chrome('C:\scrapy\chromedriver', chrome_options=chrome_options)
    driver.get('https://servicosonline.cpfl.com.br/agencia-webapp/#/login')
    sleep(15)
    element = WebDriverWait(driver, 600).until(EC.presence_of_element_located((By.ID, 'encontrarInstalacao')))
    #Clicar no checkbox do email
    email = driver.find_element_by_xpath('//*[@translate="@APP-COMMON-EMAIL"]')
    email.click()

    #Digitar email
    username = driver.find_element_by_id('documentoEmail')
    username.send_keys('email')
    sleep(0.5)

    #Digitar Senha
    password = driver.find_element_by_id('senha')
    password.send_keys('password')
    sleep(0.5)

    #Clicar botao para logar
    sign_in_button = driver.find_element_by_xpath('//*[@valeutype="submit"]')
    sign_in_button.click()
    sleep(2)
    element = WebDriverWait(driver, 120).until(EC.presence_of_element_located((By.ID, 'selInstalacao')))

    #Localizar botão Para procurar unidade
    search_button = driver.find_element_by_xpath('//*[@type="search"]')
    search_button.click()
    sleep(0.5)

    #Achar Unidades
    if a == 1:

        actions = ActionChains(driver)
        actions.send_keys('25805681') # Pressionar o C
        actions.perform()

        teste = driver.find_element_by_xpath('//*[@class="ui-select-choices-row ng-scope active"]')
        teste.click()
        sleep(1)
     elif a == 9:      

    #trocar nome e pasta do arquivo
    os.rename('C:/scrapy/' + 'conta-completa.pdf','C:/scrapy/teste/' + '38085143.pdf')
    #trocar nome de arquivos da pasta
    original_dir = 'C:/scrapy/teste'
    for n, file_name in enumerate(os.listdir(original_dir), 1):
        full_path = os.path.join(original_dir, file_name)
        if (os.path.isfile(full_path) and '{}_'.format(n) not in file_name):
            os.rename(full_path, '{}/{}_{}'.format(original_dir, n, file_name))

    actions = ActionChains(driver)
    actions.send_keys('39615529')
    actions.perform()

    teste = driver.find_element_by_xpath('//*[@class="ui-select-choices-row ng-scope active"]')
    teste.click()
    sleep(1)

... goes to elif 64
else:      

        #trocar nome e pasta do arquivo
        os.rename('C:/scrapy/' + 'conta-completa.pdf','C:/scrapy/teste/' + '4001760792.pdf')
        #trocar nome de arquivos da pasta
        original_dir = 'C:/scrapy/teste'
        for n, file_name in enumerate(os.listdir(original_dir), 1):
            full_path = os.path.join(original_dir, file_name)
            if (os.path.isfile(full_path) and '{}_'.format(n) not in file_name):
                os.rename(full_path, '{}/{}_{}'.format(original_dir, n, file_name))
        sleep(2)


    #Clicar no acessar
    acessar = driver.find_element_by_xpath('//*[@class="btn btn-default btn-lg btn-block ng-scope"]')
    acessar.click()
    sleep(4)
    element = WebDriverWait(driver, 120).until(EC.presence_of_element_located((By.ID, 'btnPagar')))

    #Clicar Botão Segunda Via
    segunda_via = driver.find_element_by_xpath('//*[@class="card-vertical-align ng-scope"]')
    segunda_via.click()
    #sleep(10)

    element = WebDriverWait(driver, 120).until(EC.presence_of_element_located((By.ID, 'debitosPendentes')))
    pdf = driver.find_elements_by_xpath('//*[@class="btn btn-default btn-segunda-via-aberta ng-scope"]')
    driver.execute_script("arguments[0].click();", pdf[0])
    sleep(2)

    element = WebDriverWait(driver, 120).until(EC.presence_of_element_located((By.ID, 'btnVerContaCompleta')))  
    conta_completa = driver.find_element_by_id('btnVerContaCompleta')
    conta_completa.click()
    sleep(20)
    a = a + 1
    print ('Todas faturas Baixadas')
    driver.quit()