Slightly different problem for me from the answers given above. For me, the HTML markup was fine, but one of my columns in the javascript was missing and didn't match the html.
i.e.
<table id="companies-index-table" class="table table-responsive-sm table-striped">
<thead>
<tr>
<th>Id</th>
<th>Name</th>
<th>Created at</th>
<th>Updated at</th>
<th>Count</th>
</tr>
</thead>
<tbody>
@foreach($companies as $company)
<tr>
<td>{{ $company->id }}</td>
<td>{{ $company->name }}</td>
<td>{{ $company->created_at }}</td>
<td>{{ $company->updated_at }}</td>
<td>{{ $company->count }}</td>
</tr>
@endforeach
</tbody>
</table>
My Script:-
<script>
$(document).ready(function() {
$('#companies-index-table').DataTable({
serverSide: true,
processing: true,
responsive: true,
ajax: "{{ route('admincompanies.datatables') }}",
columns: [
{ name: 'id' },
{ name: 'name' },
{ name: 'created_at' },
{ name: 'updated_at' }, <-- I was missing this line so my columns didn't match the thead section.
{ name: 'count', orderable: false },
],
});
});
</script>