Try Below Code -
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By
driver = webdriver.Chrome()
action = ActionChains(driver)
driver.get('https://www.vtiger.com/begin-free-trial/')
driver.find_element_by_name('email').send_keys("xyz")
driver.find_element_by_xpath('//button[contains(text(),"Next")]').click()
messagetoVerify = "Please include an '@' in the email address. 'xyz' is missing an '@'."
myValidationmsg = driver.find_element(By.NAME, 'email').get_attribute("validationMessage")
if myValidationmsg == messagetoVerify:
print("Verified Validation Message")
Output -
Please include an '@' in the email address. 'xyz' is missing an '@'.
Note - Mark as answer if it resolves your issue.