J'ai aussi, du réseau Free, avec Firefox 87.0 (windows 10) une erreur https : PR_CONNECT_RESET_ERROR
Avec un curl (sous Ubuntu 20.04), j'ai la même erreur 'reset by peeer'.
Donc cela ne semble pas venir du réseau, mais du site ?
~$ curl -v https://www.parionssport.fdj.fr/
* Trying 194.4.208.38:443...
* TCP_NODELAY set
* Connected to www.parionssport.fdj.fr (194.4.208.38) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server did not agree to a protocol
* Server certificate:
* subject: businessCategory=Private Organization; jurisdictionC=FR; jurisdictionST=▒le-de-France; jurisdictionL=Nanterre; serialNumber=315 065 292; C=FR; L=Boulogne Billancourt; O=La Francaise Des Jeux S.A.; CN=www.parionssport.fdj.fr
* start date: Feb 9 00:00:00 2021 GMT
* expire date: Mar 12 23:59:59 2022 GMT
* subjectAltName: host "www.parionssport.fdj.fr" matched cert's "www.parionssport.fdj.fr"
* issuer: C=US; O=DigiCert Inc; OU=www.digicert.com; CN=DigiCert SHA2 Extended Validation Server CA
* SSL certificate verify ok.
> GET / HTTP/1.1
> Host: www.parionssport.fdj.fr
> User-Agent: curl/7.68.0
> Accept: */*
>
* OpenSSL SSL_read: Connection reset by peer, errno 104
* Closing connection 0
curl: (56) OpenSSL SSL_read: Connection reset by peer, errno 104