@luke thanks for your answer and debugging details but unfortunately I can provide almost none of the info you’re asking to track down our failing requests (next time I’ll know better).
And, yes, of course the certificate now looks fine because it have been renewed (the screenshot you’ve attached is showing the new one).
My main question was when to expect (in average) the new SSL certificate to be requested to Let’s Encrypt and consequently processed.
My assumption was that after clicking “renew certificate”, the new one would be available in a short time, I suppose also taking into account some delays anyway due to Netlify CDN not yet updated.
Also, it is not clear to me why did I have to manually force the SSL cert renewal in the first place, isn’t that automatically renewed 10 days before expiry? Possibly our DNS configuration for the domain does not allow you to do that? What will happen in three months? Should we schedule the new renewal by ourselves of Netlify will manage that automatically?
Everything’s fine, I was just confused because I couldnt really understand the sequence of events that led to the solution.
Thanks again for any clarification you may provide.
Regards,