Hi Xavier,
> Is your proxy supporting https GET requests ?> httrack is currently unable
to use the pass-through
> feature (CONNECT) and rely on direct GET commands in
> clear text.

thank you for explanation, that answers the question.
I doublechecked and for https my proxy requires CONNECT. When I  just perform
a GET on https content I get this header:
X-Squid-Error: ERR_UNSUP_REQ 0


best regards
Laura