ERR_EMPTY_RESPONSE when visiting pvoutput.org

ThooneR

Bitdefender Antivirus Free on Windows 10 version 20H2

when I try to visit https://pvoutput.org/ I get an ERR_EMPTY_RESPONSE (in all browsers)

When I add pvoutput.org URL in the exclusion list in Bitdefender Antivirus Free, it works

The certificate used by pvoutput.org is :

CN = R3 O = Let’s Encrypt C = US