gosha Did you try to re-issue a new certificate? I would Request Let's Encrypt certificate again because in Enhance if an SSL certificate already exists on your domain it will then be replaced automatically.
I've already tested that and it worked for me.
You can also install manually your own certificate (Title of this post). If you use CF for instance, you can download CF origin certificate then go in Enhance > Advanced > Security and click on the "Install custom SSL certificate" button. Note that 3 days before the expiry of a third party certificate CF in this case, Enhance will automatically request a Let's Encrypt certificate.