Advanced search form not displayed

Hello. I’m doing a fresh install of Omeka and am finding that the advanced search form is not displaying correctly.
To start, I use the Seasons theme, so I looked at this topic. However, when changing the theme the problem remains, which makes me rule out that the choice of theme is the problem.
I have also seen this topic, but my version of Omeka is 3.1.2 .
I don’t know what could be happening.
Next, I paste the content of the core’s search-form.php (since the theme does not have such a page)

<?php echo $this->form('search-form', $options['form_attributes']); ?>
    <?php 
        echo $this->formText('query', $filters['query'], array(
            'title' => __('Query'), 
            'aria-label' => __('Query'), 
            'aria-labelledby' => 'search-form query'
        )); 
    ?>
    <?php if ($options['show_advanced']): ?>
    <button id="advanced-search" type="button" class="show-advanced button" aria-label="<?php echo __('Options'); ?>" title="<?php echo __('Options'); ?>" aria-labelledby="search-form advanced-search">
        <span class="icon" aria-hidden="true"></span>
    </button>
    <div id="advanced-form">
        <fieldset id="query-types">
            <legend><?php echo __('Search using this query type:'); ?></legend>
            <?php echo $this->formRadio('query_type', $filters['query_type'], null, $query_types); ?>
        </fieldset>
        <?php if ($record_types): ?>
        <fieldset id="record-types">
            <legend><?php echo __('Search only these record types:'); ?></legend>
            <?php foreach ($record_types as $key => $value): ?>
            <?php echo $this->formCheckbox('record_types[]', $key, array('checked' => in_array($key, $filters['record_types']), 'id' => 'record_types-' . $key)); ?> <?php echo $this->formLabel('record_types-' . $key, $value);?><br>
            <?php endforeach; ?>
        </fieldset>
        <?php elseif (is_admin_theme()): ?>
            <p><a href="<?php echo url('settings/edit-search'); ?>"><?php echo __('Go to search settings to select record types to use.'); ?></a></p>
        <?php endif; ?>
        <p><?php echo link_to_item_search(__('Advanced Search (Items only)')); ?></p>
    </div>
    <?php else: ?>
        <?php echo $this->formHidden('query_type', $filters['query_type']); ?>
        <?php foreach ($filters['record_types'] as $type): ?>
        <?php echo $this->formHidden('record_types[]', $type, array('id' => '')); ?>
        <?php endforeach; ?>
    <?php endif; ?>
    <?php 
        echo $this->formButton('submit_search', $options['submit_value'], array(
            'type' => 'submit', 
            'title' => __('Submit'), 
            'class' => 'button', 
            'content' => '<span class="icon" aria-hidden="true"></span>', 
            'escape' => false,
            'aria-label' => __('Submit'),
            'aria-labelledby' => 'search-form submit_search'
            )
        ); 
    ?>
</form>

And this is the page of the failed search. It is also the only page where “Tecnología de Omeka” cannot be read in the footer. In the rest of Omeka’s pages it appears normally.

PS: I have the advanced search option enabled in the theme settings.

Your observation that the footer isn’t loading is key here. The advanced search functionality isn’t working because the line of code that triggers it is usually in the footer.

Could you remove all your changes from the theme and list what plugins you have installed?

You might also want to try the Display Error Messages instructions here, or checking your server’s PHP log (not the Omeka log). This type of situation where the page stops partway through usually indicates a fatal error, for which it would be helpful to know the exact error message.