Using HTML tag make Worpress crash

Good Morning,

Since version 1.0.37, my WordPress website is crashing on page using the HTML shortcode : [click5_sitemap].

Checked in logs and find this entry :

2022/04/17 11:26:07 [error] 1412#1412: *350542 FastCGI sent in stderr: "PHP message: PHP Warning:  Invalid argument supplied for foreach() in /var/www/wp-content/plugins/sitemap-by-click5/api.php on line 2437
PHP message: PHP Fatal error:  Uncaught Error: Object of class WP_Error could not be converted to string in /var/www/wp-content/plugins/sitemap-by-click5/HTMLsitemap.php:785
Stack trace:
    #0 /var/www/wp-content/plugins/sitemap-by-click5/HTMLsitemap.php(905): HTMLSitemapList->displayGroup()
    #1 /var/www/wp-content/plugins/sitemap-by-click5/HTMLsitemap.php(973): HTMLSitemapList->displaySubchilds()
    #2 /var/www/wp-content/plugins/sitemap-by-click5/api.php(663): HTMLSitemapList->display()
    #3 /var/www/wp-includes/shortcodes.php(356): click5_sitemap_display_sitemap()
    #4 [internal function]: do_shortcode_tag()
    #5 /var/www/wp-includes/shortcodes.php(228): preg_replace_callback()
    #6 /var/www/wp-includes/class-wp-hook.php(307): do_shortcode()
    #7 /var/www/wp-includes/plugin.php(189): WP_Hook->apply_filters(" while reading response header from upstream, client: 78.196.133.168, server: *, request: "POST /wp-admin/post.php?post=3300&action=edit&meta-box-loader=1&meta-box-loader-nonce=aaf3a75fd7&_locale=user HTTP/2.0", upstream: "fastcgi://unix:/var/run/php/php7.4-fpm-wordpress.sock:", host: "*", referrer: "https://*/wp-admin/post.php?post=3300&action=edit"