After you clicked loginenter button, some wait should be added to reload page. It will provide small delay which is helpful for SeleniumDriver to identify element. I would like to suggest you to add some condition to wait next element. Please try below code snippet

WebElement myDynamicElement = 
(new WebDriverWait(driver, 10)).until(ExpectedConditions.presenceOfElementLocated(By.id("usrUTils")));

All you have to do is switch to the frame before you try to locate the elements, like the following:

driver.switchTo().frame("UWPIFrame");

Your code will look like this:

@Test(dataProvider="homeLoan")
public void homeLoan(String fullname, String email, String countryTypes, String postcode, String phone, String loanType, String loanPurposes, String securityValue, String homeLoanAmount) throws Exception {
    // open | https://test-www.loans.com.au/
    driver.get("https://test-www.loans.com.au/");
    // click | link=contact | 
    driver.findElement(By.linkText("contact")).click();
    //Switch to the frame 
    driver.switchTo().frame("UWPIFrame");
    // type | name=FullName
    driver.findElement(By.name("FullName")).clear();
    driver.findElement(By.name("FullName")).sendKeys(fullname);
    // type | name=Email
    driver.findElement(By.name("Email")).clear();
    driver.findElement(By.name("Email")).sendKeys(email);

But remember, if you try to locate another Element that is not in the iframe you will need to switch back to the default content like this:

driver.switchTo().defaultContent();

As Yuvaraj HK has mentioned ,using implicit wait just once in your code would be enough.It'l implicitly wait for every element that you try to find in your code.

chrome.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

But try to keep implicit wait time as low as possible, because this might increase your code execution time..

In some cases the element might take more than 30 seconds to be visible, Explicit wait can be used in these kind of situations.

WebDriverWait some_element = new WebDriverWait(driver,100); 
some_element.until(ExpectedConditions.visibilityOfElementLocated(By.id("id_of_some_element")));
//do anything you want with some_element

I strongly suggest using cssSelectors over xpath. This article might help.
Even if xpath is used, try using shorter ones. Using an id is not the only way to reach an element. Its parent might have unique class names or other attributes, which you can use to create efficient xpaths or cssSelectors.

driver.switchTo().frame(0);
WebElement guichet = driver.findElement(By.xpath("//input[@name='Guichet']"));
WebElement matricule = driver.findElement(By.name("Matricule"));
WebElement password = driver.findElement(By.name("Mot_de_passe"));
WebElement save = driver.findElement(By.name("Valider"));
//Entering text into the email field
guichet.sendKeys("0000");

matricule.sendKeys("login");
password.sendKeys("password");
save.click();
driver.switchTo().defaultContent();

You should be using dynamic selectors. http://pragmatictestlabs.com/2018/05/16/mastering-xpath-for-selenium-test-automation/

This is certainly a tough xpath if you're just starting but if you want to click the "Business" button in the header it would be:

driver.findElement(By.xpath("//header[@id='header-nav-container'] //div[contains(@class,'NavGrid')] [not(@style='false:unset')]//a[text()='Business']"));

As for all the error messages, I'm not sure why it's throwing them. What's missing actually is the Exception that should be thrown when the findElement method failed. I believe it should be a NoSuchElement Exception.

Can you surround your code with a try/catch block and throw an Exception like so:

try {
//code
} catch (Exception e) {
System.out.println(e) 
}

EDIT: Actually, it is throwing the NoSuchElementException. I guess Geckodriver throws it in the midst of other log entries. Exception in thread "main" org.openqa.selenium.NoSuchElementException: Unable to locate element: /html[1]/body[1]/div[5]/div[1]/div[1]/header[1]/div[1]/div[1]/div[1]/div[2]/nav[1]/ul[1]/li[3]/a[1]

You can try implementing WebDriver wait for this -

Webdriver driver;
WebDriverWait wait = new WebDriverWait(driver, 100);
element= wait.until(ExpectedConditions.elementToBeClickable(By.XPATH("//span[contains(text(),'Hotel Log')]")));

If you are getting NoSuchElementException as your provided exception, There may be following reasons :-

• May be when you are going to find element, it would not be present on the DOM, So you should implement WebDriverWait to wait until element visible as below :-

  WebDriverWait wait = new WebDriverWait(driver, 10);
  WebElement Category_Body = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("tinymce")));
   Category_Body.sendKeys("Android Smart Phone - 16GB");
  

• May be this element is inside any frame or iframe. If it is, you need to switch that frame or iframe before finding the element as below :-

  WebDriverWait wait = new WebDriverWait(driver, 10);
  
  //Find frame or iframe and switch
  wait.until(ExpectedConditions.frameToBeAvailableAndSwitchToIt("your frame id or name"));
  
  //Now find the element 
  WebElement Category_Body = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("tinymce")));
   Category_Body.sendKeys("Android Smart Phone - 16GB");
  
  //Once all your stuff done with this frame need to switch back to default
  driver.switchTo().defaultContent();
  

NoSuchElementException

org.openqa.selenium.NoSuchElementException popularly known as NoSuchElementException extends org.openqa.selenium.NotFoundException which is a type of WebDriverException.

NoSuchElementException can be thrown in 2 cases as follows :

• When using WebDriver.findElement(By by) :

  //example : WebElement my_element = driver.findElement(By.xpath("//my_xpath"));
  

• When using WebElement.findElement(By by) :

  //example : WebElement my_element = element.findElement(By.xpath("//my_xpath"));
  

As per the JavaDocs just like any other WebDriverException, NoSuchElementException should contain the following Constant Fields :

Constant Field      Type                                        Value
SESSION_ID          public static final java.lang.String        "Session ID"
e.g. (Session info: chrome=63.0.3239.108)

DRIVER_INFO         public static final java.lang.String        "Driver info"
e.g. (Driver info: chromedriver=2.34.522940 (1a76f96f66e3ca7b8e57d503b4dd3bccfba87af1),platform=Windows NT 6.1.7601 SP1 x86)

BASE_SUPPORT_URL    protected static final java.lang.String     "http://seleniumhq.org/exceptions/"
e.g. (For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html)

Reason

The reason for NoSuchElementException can be either of the following :

• The Locator Strategy you have adopted doesn't identifies any element in the HTML DOM.
• The Locator Strategy you have adopted is unable to identify the element as it is not within the browser's Viewport.
• The Locator Strategy you have adopted identifies the element but is invisible due to presence of the attribute style="display: none;".
• The Locator Strategy you have adopted doesn't uniquely identifies the desired element in the HTML DOM and currently finds some other hidden / invisible element.
• The WebElement you are trying to locate is within an <iframe> tag.
• The WebDriver instance is looking out for the WebElement even before the element is present/visibile within the HTML DOM.

Solution

The solution to address NoSuchElementException can be either of the following :

• Adopt a Locator Strategy which uniquely identifies the desired WebElement. You can take help of the Developer Tools (Ctrl+Shift+I or F12) and use Element Inspector.

  Here you will find a detailed discussion on how to inspect element in selenium3.6 as firebug is not an option any more for FF 56?

• Use executeScript() method to scroll the element in to view as follows :

  WebElement elem = driver.findElement(By.xpath("element_xpath"));
  ((JavascriptExecutor)driver).executeScript("arguments[0].scrollIntoView();", elem);
  

  Here you will find a detailed discussion on Scrolling to top of the page in Python using Selenium

• Incase element is having the attribute style="display: none;", remove the attribute through executeScript() method as follows :

  WebElement element = driver.findElement(By.xpath("element_xpath"));
  ((JavascriptExecutor)driver).executeScript("arguments[0].removeAttribute('style')", element)
  element.sendKeys("text_to_send");
  

• To check if the element is within an <iframe> traverse up the HTML to locate the respective <iframe> tag and switchTo() the desired iframe through either of the following methods :

  driver.switchTo().frame("frame_name");
  driver.switchTo().frame("frame_id");
  driver.switchTo().frame(1); // 1 represents frame index
  

  Here you can find a detailed discussion on Is it possible to switch to an element in a frame without using driver.switchTo().frame(“frameName”) in Selenium Webdriver Java?.

• If the element is not present/visible in the HTML DOM immediately, induce WebDriverWait with ExpectedConditions set to proper method as follows :

  • To wait for presenceOfElementLocated :

    new WebDriverWait(driver, 20).until(ExpectedConditions.presenceOfElementLocated(By.xpath("//div[@class='buttonStyle']//input[@id='originTextField']")));
    

  • To wait for visibilityOfElementLocated :

    new WebDriverWait(driver, 20).until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//div[@class='buttonStyle']//input[@id='originTextField']")));
    

  • To wait for elementToBeClickable :

    new WebDriverWait(driver, 20).until(ExpectedConditions.elementToBeClickable(By.xpath("//div[@class='buttonStyle']//input[@id='originTextField']")));
    

Reference

You can find Selenium's python client based relevant discussion in:

• Selenium “selenium.common.exceptions.NoSuchElementException” when using Chrome

Use wait() method properly so that the desired element is visible/present.

Your code seems okay. You can recheck the xpath of button. Use click() method instead of sendKeys(Keys.RETURN);

 // Click purchase button
    driver.findElement(By.xpath("//*[@id=\"chakra-modal--body-630\"]/button")).click();