Newsletter form in sidebar

Hello david, although I indicated in the form the width: <table width = "200">, the form is represented over the sideboard.

Where can the error lie here?

<form action="https://click.isolsend.com/subscribe" class="legacy" method="post">
<table width="200">
<tr>
<td>Vorname*</td>
<td><input type="text" name="firstname" value="" data-label="Vorname" data-rules="trim|required" /></td>
</tr>
<tr>
<td>Email*</td>
<td><input type="text" name="email" value="" data-label="Email" data-rules="trim|required|valid_email" /></td>
</tr>
<tr>
<td> </td>
<td><input type="submit" name="action" value="Absenden" /></td>
</tr>
</table>
<input type="hidden" name="project_id" value="415900" />
<input type="hidden" name="customer_id" value="285440" />
<input type="hidden" name="group_id" value="1199024" />
</form>