Doesn't work behind network proxy with authentication

[GuittonHubert]

Hello,

I'm trying to use htpdate behind a network proxy with authentication. Proxy username/password are set (and url-encoded) in the proxy URL as follows:

sudo ./htpdate -t -d -q -P http://${PROXY_USER}:${PROXY_PASSWD}@${PROXY_HOSTNAME}:${PROXY_PORT}  jjy.nict.go.jp

jjy.nict.go.jp host or service unavailable
No server suitable for synchronization found

I also tried without success different declaration of the proxy:

• without or without http://
• with or with url-encoding the username/password.

Any idea?

PS: I'm using a freshly compiled version of htpdate: commit 7964ca0 on Linux Ubuntu 18.04.6 LTS