It’s been resolved.
For some reason, upon updating the SSL certificate, my htaccess contained a rewrite rule
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?mydomain.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?mydomain.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?google.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?google.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://checkout.stripe.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http(s)?://checkout.stripe.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://(.*)?mydomain.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://(.*)?mydomain.com$ [NC]
RewriteRule .*\.(.*)$ http://%{REMOTE_ADDR}/$ [R,NC]
so I changed it to a simpler
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
So, unless you got something to say in terms of safety, I reckon this issue is resolved.