Here is the HTML code, i\'m trying to select \'select customer\' drop-down.
First check that:
Drop down in your UI/FrontEnd is using "select" method or not ?
And if not then use below snippet that will click in drop down and select value.
WebElement selectMyElement = driver.findElement(this.getObject(By.Id("Id of Your DropDown")));
selectMyElement.click();
Actions keyDown = new Actions(driver);
keyDown.sendKeys(Keys.chord(Keys.DOWN, Keys.DOWN)).perform();