No results with only categories

<!-- SEARCH RESULTS -->

        {exp:low_search:results
            query='{freebie_3}'
            channel='vacatures'
            status='not closed'
            require_all='category'
            search_mode='all'
            keywords:loose='both'
            disable='category_fields|member_data|pagination'
        }
            {if no_results}
                {if low_search_keywords != "" || low_search_category != ""}
                <tr><td colspan="2"><div class="alert alert-info"><strong>Er zijn geen resultaten gevonden.</strong><br />Hieronder ziet u alle vacatures.</div></td></tr>
                {/if}

                {exp:channel:entries
                    channel='vacatures'
                    orderby='vacature_top_vacature'
                    sort='desc'
                    dynamic='no'
                    status='not closed'
                }
                <tr>
                  <td class="title"><a href="/vacature/{url_title}" class="title{if vacature_top_vacature} top{/if}" title="Bekijk vacature {url_title}">{title} {vacature_top_vacature}</a><br>{vacature_kernwoorden}</td>
                  <td align="right" width="150"><a href="/vacature/{url_title}" class="details">Bekijk nu <i class="fa fa-angle-right fa-2x"></i></a></td>
                </tr>
                {/exp:channel:entries}
            {/if}

                <tr>
                  <td class="title"><a href="/vacature/{url_title}" class="title{if vacature_top_vacature} top{/if}" title="Bekijk vacature {url_title}">{title} {vacature_top_vacature}</a><br>{vacature_kernwoorden}</td>
                  <td align="right" width="150"><a href="/vacature/{url_title}" class="details">Bekijk nu <i class="fa fa-angle-right fa-2x"></i></a></td>
                </tr>

        {/exp:low_search:results}





<!-- SEARCH FORM -->
{exp:low_search:form
            query='{freebie_3}'
        }
                <div class="jobsearch">
                    <h2><i class="fa fa-search"></i>&nbsp;&nbsp;Jobsearch</h2>
                    <div class="form-group">
                        <input type="search" name="keywords" id="keywords" placeholder="Vacatures / trefwoorden" value="{low_search_keywords}" />
                    </div>
                    <div class="form-group">
                        <select name="category[]">
                            <option value="">Alle Branches</option>
                            {exp:channel:categories category_group="1" style="linear"}
                                <option value="{category_id}"{if low_search_category ~ '/\b'.category_id.'\b/'} selected{/if}>
                                  {category_name}
                              </option>
                            {/exp:channel:categories}
                        </select>
                    </div>
                    <div class="form-group">
                        <select name="category[]">
                            <option value="">Alle Provincies</option>
                            {exp:channel:categories category_group="7" style="linear"}
                                <option value="{category_id}"{if low_search_category ~ '/\b'.category_id.'\b/'} selected{/if}>
                                  {category_name}
                              </option>
                            {/exp:channel:categories}

                        </select>
                    </div>
                    <button class="btn btn-block btn-primary" type="submit">Zoeken</button>
                </div>
        {/exp:low_search:form}