title: Creating a single exact project, POST results in 500 error
body: <p>I have access to Exact (OAUTH), access-, refresh-tokens, division No. ...<br />
  I get, 'GET' information From Exact API.<br />
  But I have problems in 'POST'-ing a new project, using Exact API.<br />
  And I have no Clue what is the problem.</p>
  <p>As a user, I have 'POST' privileges ().</p>
  <blockquote>
  <p><code>https://start.exactonline.nl/api/v1/2999609/Users/UserHasRights?endpoint='project/Projects'&amp;action='POST'</code> =&gt; true</p>
  </blockquote>
  <p>I've no clue what to do next. Maybe I need to provide more <code>data</code>, but the documentations, state those three fields are enough to create a project.</p>
  <pre><code>const data = {
      &quot;Code&quot;:&quot;P99A&quot;,
      &quot;Description&quot;:&quot;P99A Descr&quot;,
      &quot;Type&quot;: 1
  }
  
  const response = await fetch('https://start.exactonline.nl/api/v1/2999609/project/Projects', {  
      method: 'POST',  
      headers: {  
          'Accept': 'application/json',  
          'Content-Type': 'application/json',  
          'Prefer': 'return=representation',  
          'Authorization': `Bearer ${accessToken}`  
      },
      body: JSON.stringify(data)
  })
  console.log(response)
  </code></pre>
  <p>Exact Server response:</p>
  <pre><code>Response {  
    size: 0,  
    timeout: 0,  
    [Symbol(Body internals)]: {  
      body: PassThrough {  
        _readableState: [ReadableState],  
        _events: [Object: null prototype],  
        _eventsCount: 2,  
        _maxListeners: undefined,  
        _writableState: [WritableState],  
        allowHalfOpen: true,  
        [Symbol(kCapture)]: false,  
        [Symbol(kCallback)]: null  
      },  
      disturbed: false,  
      error: null  
    },  
    [Symbol(Response internals)]: {  
      url: 'https://start.exactonline.nl/api/v1/2999609/project/Projects',  
      status: 500,  
      statusText: 'Internal Server Error',  
      headers: Headers { [Symbol(map)]: [Object: null prototype] },  
      counter: 0  
    }  
  }  
  </code></pre>