Failed to access sitemap

Hello i have installed rankmath on my blog but i cannot access sitemap, it gives a fatal error.

Why it needs FTP access ?

[client 162.158.19.91:0] PHP Fatal error: Uncaught TypeError: ftp_mkdir(): Argument #1 ($ftp) must be of type FTP\\Connection, null given in /var/www/html/blog/wp-admin/includes/class-wp-filesystem-ftpext.php:580\nStack trace:\n#0 /var/www/html/blog/wp-admin/includes/class-wp-filesystem-ftpext.php(580): ftp_mkdir(NULL, ‘/var/www/html/b…’)\n#1 /var/www/html/blog/wp-content/plugins/seo-by-rank-math/includes/modules/sitemap/class-cache.php(80): WP_Filesystem_FTPext->mkdir(‘/var/www/html/b…’, 493)\n#2 /var/www/html/blog/wp-content/plugins/seo-by-rank-math/includes/modules/sitemap/class-cache.php(53): RankMath\\Sitemap\\Cache->is_writable()\n#3 /var/www/html/blog/wp-content/plugins/seo-by-rank-math/includes/modules/sitemap/class-sitemap-xml.php(80): RankMath\\Sitemap\\Cache->__construct()\n#4 /var/www/html/blog/wp-content/plugins/seo-by-rank-math/includes/modules/sitemap/class-router.php(79): RankMath\\Sitemap\\Sitemap_XML->__construct(‘1’)\n#5 /var/www/html/blog/wp-includes/class-wp-hook.php(310): RankMath\\Sitemap\\Router->request_sitemap(Object(WP_Query))\n#6 /var/www/html/blog/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters(”, Array)\n#7 /var/www/html/blog/wp-includes/plugin.php(565): WP_Hook->do_action(Array)\n#8 /var/www/html/blog/wp-includes/class-wp-query.php(1140): do_action_ref_array(‘parse_query’, Array)\n#9 /var/www/html/blog/wp-includes/class-wp-query.php(1868): WP_Query->parse_query()\n#10 /var/www/html/blog/wp-includes/class-wp-query.php(3800): WP_Query->get_posts()\n#11 /var/www/html/blog/wp-includes/class-wp.php(662): WP_Query->query(Array)\n#12 /var/www/html/blog/wp-includes/class-wp.php(782): WP->query_posts()\n#13 /var/www/html/blog/wp-includes/functions.php(1335): WP->main(”)\n#14 /var/www/html/blog/wp-blog-header.php(16): wp()\n#15 /var/www/html/blog/index.php(17): require(‘/var/www/html/b…’)\n#16 {main}\n thrown in /var/www/html/blog/wp-admin/includes/class-wp-filesystem-ftpext.php on line 580
162.158.19.91 – – [02/Nov/2023:08:12:14 +0000] “GET /blog/sitemap_index.xml HTTP/1.1” 500 3116 “-” “Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36”

PS: define(‘FS_METHOD’,’direct’); is defined in wp-config