eclipse サーバー実行時に「サーバー ローカル・ホスト の Tomcat8 (Java8) は始動に失敗しました。」と表示されて起動できない

Question

前提・実現したいこと

メール送信を行うプログラムを作成してサーバーで実行したのですが、「サーバー ローカル・ホスト の Tomcat8 (Java8) は始動に失敗しました。」と表示されて起動できません。テラテイルの質問にも類似の投稿があったため、参考にしたのですが、解決できずでどなたかご助力お願いしたいです。

参考にしたURL
https://www.youtube.com/watch?v=0ignaDR1UOs&t=269s

###実行環境
eclipseのバージョン Oxygen.3a Release (4.7.3a)
Tomcat Tomcat8

###試したこと
サーバーを削除して再度作成し、実行
pom.xmlを削除して実行(pom.xmlを削除して実行したところ、jspが表示されたのでこいつが原因かと考えています。)

発生している問題・エラーメッセージ

重大: A child container failed during start [月 11 29 17:08:08 GMT+09:00 2021]
重大: A child container failed during start [月 11 29 17:08:08 GMT+09:00 2021]
重大: The required Server component failed to start so Tomcat is unable to start. [月 11 29 17:08:08 GMT+09:00 2021]
情報: Pausing ProtocolHandler ["http-nio-8080"] [月 11 29 17:08:08 GMT+09:00 2021]
情報: Pausing ProtocolHandler ["ajp-nio-8009"] [月 11 29 17:08:08 GMT+09:00 2021]
情報: サービス Catalina を停止します [月 11 29 17:08:08 GMT+09:00 2021]
情報: Destroying ProtocolHandler ["http-nio-8080"] [月 11 29 17:08:08 GMT+09:00 2021]
重大: Failed to destroy end point associated with ProtocolHandler ["http-nio-8080"] [月 11 29 17:08:08 GMT+09:00 2021]
情報: Destroying ProtocolHandler ["ajp-nio-8009"] [月 11 29 17:08:08 GMT+09:00 2021]
重大: Failed to destroy end point associated with ProtocolHandler ["ajp-nio-8009"] [月 11 29 17:08:08 GMT+09:00 2021]

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>poly.edu</groupId>
  <artifactId>DemoSendEmail</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>DemoSendEmail</name>
  <description>DemoSendEmail</description>
  <dependencies>
<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4</version>
</dependency>
  </dependencies>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.7.0</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>3.0.0</version>
        <configuration>
          <warSourceDirectory>WebContent</warSourceDirectory>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

package poly.edu;

import java.io.IOException;
import java.util.Properties;

import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class SendMailServlet
 */
@WebServlet("/SendMailServlet")
public class SendMailServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public SendMailServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		RequestDispatcher rd = request.getRequestDispatcher("views/sendemail.jsp");
		rd.forward(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		final String username = "[e-mail]";
		final String password = "xxxxxxxxx";
		Properties prop = new Properties();
		prop.put("mail.smtp.host", "smtp.gmail.com");
		prop.put("mail.smtp.port", "587");
		prop.put("mail.smtp.auth", "true");
		prop.put("mail.smtp.starttls.enable", "ture"); //TLS
		Session session = Session.getInstance(prop, new javax.mail.Authenticator(){
			protected PasswordAuthentication getPasswordAuthentication() {
			return new PasswordAuthentication(username,password);
			}

		});
		//dang nhap dc email
		String emailTo = request.getParameter("to");
		String emailSubject = request.getParameter("subject");
		String emailContent = request.getParameter("content");
		try {
			Message message = new MimeMessage(session);
			message.setFrom(new InternetAddress(username));
			message.setRecipients(
					Message.RecipientType.TO,
					InternetAddress.parse(emailTo)
					//	InternetAddress.parse("[e-mail], [e-mail]")
						);
			message.setSubject(emailSubject);
			message.setText(emailContent);
			Transport.send(message);
			System.out.println("Done");
		}catch (Exception e) {
			//TODO: handle exception
		}
	}

}

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<link rel="stylesheet"
	href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/css/bootstrap.min.css">
<script
	src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script
	src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/js/bootstrap.min.js"></script>
<title>JSP Page</title>
</head>
<body>
	<div class="container" style="margin-top: 10px;">
		<div class="row"
			style="border: 1px darkgrey solid; border-radius: 10px; width: 50%; margin: 0 auto; padding: 20px;">
			<div class="col-sm-12">
				<h2 class="myclass">Information</h2>
				<form action="./SendMailServlet" method="post">
					<div class="form-group">
						<label>To:</label>
						<input type="text"
						class="form-control" name="to" placeholder="Enter Email">
					</div>
					<div class="form-group">
						<label>Subject:</label>
						<input type="text"
						class="form-control" name="subject" placeholder="Enter Subject">
					</div>
					<div class="form-group">
						<label for="content">Content:</label>
						<textarea class="form-control" rows="3"  name="content"></textarea>
					</div>
					<button type="submit" class="btn btn-primary">Send</button>
					<button type="reset" class="btn btn-primary">Cancel</button>
				</form>
			</div>
		</div>
	</div>
</body>
</html>