Plugins do not update

Hi all,
I have just updated WordPress to 5.6, but it is since three weeks that I have 0 plugins (out of 31 active) that seem don’t need update, but they do.
Some times ago in the post Plugin needs update, but does not show anywhere @otto42 answered to search in the _site_transient_update_plugins table row.
I found in mine that the problem likely is contact-form-7 (O:8:"stdClass":4:{s:12:"last_checked";i:1607443908;s:8:"response";a:8:{s:36:"contact-form-7/wp-contact-form-7.php";O:8:"stdClass":12:{s:2:"id";s:28:"w.org/plugins/contact-form-7";s:4:"slug";s:14:"contact-form-7";s:6:"plugin";s:36:"contact-form-7/wp-contact-form-7.php";s:11:"new_version";s:5:"5.3.1";s:3:"url";s:45:"https://www.ads-software.com/plugins/contact-form-7/";s:7:"package";s:63:"https://downloads.www.ads-software.com/plugin/contact-form-7.5.3.1.zip";s:5:"icons";a:3:{s:2:"2x";s:67:"https://ps.w.org/contact-form-7/assets/icon-256x256.png?rev=2279696";s:2:"1x";s:59:"https://ps.w.org/contact-form-7/assets/icon.svg?rev=2339255";s:3:"svg";s:59:"https://ps.w.org/contact-form-7/assets/icon.svg?rev=2339255";}s:7:"banners";a:2:{s:2:"2x";s:69:"https://ps.w.org/contact-form-7/assets/banner-1544x500.png?rev=860901";s:2:"1x";s:68:"https://ps.w.org/contact-form-7/assets/banner-772x250.png?rev=880427";}s:11:"banners_rtl";a:0:{}s:6:"tested";s:3:"5.6";s:12:"requires_php";b:0;s:13:"compatibility";O:8:"stdClass":0:{}} etc.
I had it uninstalled, there is no folder with is name, but nor the string in the table get clean, nor I can see any plugin updates in WordPress.
Please, can anyone help me?
Thank you very much…