Spring-Boot Post request with csrf header

When developing my Spring Boot app, I had csrf disabled; but now I need to enable it. I followed the Spring Docs here but I keep getting a "SyntaxError: Invalid header name." in my javascript file making the POST request. Am I doing something obviously wrong here?

This is in my Header at the top of the HTML page for this function:

<meta name="_csrf" content="${_csrf.token}"/>
<meta name="_csrf_header" content="${_csrf.headerName}"/>

This is the JavaScript file making the request:

var request = new XMLHttpRequest();
request.onreadystatechange = function() {
  if (request.readyState == XMLHttpRequest.DONE) {
      location.reload();
  }
}

// Headers for CSRF protection
var token = $("meta[name='_csrf']").attr("content");
var header = $("meta[name='_csrf_header']").attr("content");

request.open("POST", "/admin/delete-email");
request.setRequestHeader(header, token);  <-- This line throws syntax error.
request.send(formData);

Here is the security configuration:

@Override
public void configure(HttpSecurity http) throws Exception {
  // The following snippet opens the entire app
  // http.authorizeRequests().antMatchers("/**").permitAll();

  //http.csrf().disable();
  http.authorizeRequests()
    .antMatchers("/admin/**")
    .hasRole("ADMIN")
    .antMatchers("/db/**")
    .hasRole("ADMIN")
    .and()
    .formLogin()
    .permitAll()
    .and()
    .httpBasic();
  }

I also get a 403 error when making a POST request using a Form:

<form method="POST" enctype="multipart/form-data" action="/admin/add-email">
    <td class="tg-0pky"><input type="text" name="employeeId"/></td>
    <td class="tg-0pky"><input type="text" name="email"/></td>
    <td class="tg-0pky"><input type="submit" value="Upload"/></td>
    <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/>
</form>

Figured it out. Since I am using Thymeleaf I need to use th: namespaces.

<meta th:name="_csrf" th:content="${_csrf.token}"/>
<meta th:name="_csrf_header" th:content="${_csrf.headerName}"/>

and

<form method="POST" enctype="multipart/form-data" action="/admin/add-email">
  <td class="tg-0pky"><input type="text" name="employeeId"/></td>
  <td class="tg-0pky"><input type="text" name="email"/></td>
  <td class="tg-0pky"><input type="submit" value="Upload"/></td>
  <input type="hidden" th:name="${_csrf.parameterName}" th:value="${_csrf.token}"/>
</form>