Problem WordPress RSS feed reports error

https://otzerling.com/feed/feedname
I’m not sure why… there seems to be an invalid character. I checked the original post and couldn’t find it, but this is causing mailchimp to not send the emails of events from the website, which is an urgent problem. Is there any function I could use to strip invalid characters?

Here is the code related to the text descriptions:

</description>                        
                        <?php if ( strlen( $post->post_content ) > 0 ) : ?>
                        <content:encoded><![CDATA[<?php the_content_feed('rss2') ?>]]></content:encoded>
                        <?php else : ?>
                        <content:encoded><![CDATA[<?php the_excerpt_rss() ?>]]></content:encoded>
                        <?php endif; ?>
                                    
                        <?php rss_enclosure(); ?>
                        <?php do_action('rss2_item'); ?>

• This topic was modified 3 years, 8 months ago by snippet24.
• This topic was modified 3 years, 8 months ago by snippet24.