Admin email from Let’s Encrypt free SSL

Where and how are you trying to update an SSL certificate in WordPress? WordPress doesn’t have that sort of functionality. Are you sure that it’s not something that you’re doing through your hosting account?

This error is usually when you try to perform changes from the WordPress admin panel. How are you trying to install the SSL certificate ? Are you trying to update it from WordPress admin dashboard ?

Setting WP_DEBUG to true in your wp-config.php OR enabling error logs might shed some light.

Thanks for the responses.

I am using a plugin called Auto-Install Free SSL 3.6.0 from my Dashboard.

If you mean this plugin:

https://www.ads-software.com/plugins/auto-install-free-ssl/

Then you should ask in their support forum:

https://www.ads-software.com/support/plugin/auto-install-free-ssl/

I wondered but it was the non arrival of the email to my WordPress admin email address that instigated this enquiry.