I am using a Domino server behind a Fritz!Box. I have configured Port Mapping in the FRitz!Box to map 443 -> 443. Port 80 is not open.
When I try to get a certificate, the HTTP challenge fails with a timeout.
The challenge token is accessible via https://server//html/.well-known … and I can display its content.
I would like to understand, how LE tries to validate the token.
My understanding is that LE tries on port 80 FIRST; if it does not get an answer, port 443 is being checked.
Is this so ?
If not, how can I make sure that the validation succeeds when only port 443 is open?
When I open port 80, validation is ok, BTW.