> Squid Proxy Server v3.5
> ssl_bump peek all
> ssl_bump splice all
Please upgrade to Squid v4 (at least) or stop using SslBump features,
depending on whether you actually need SslBump features. And if you do
need SslBump features, then you must configure http_port(s) accordingly.
The primary question is why is your Squid responding with a 503 error to
the CONNECT request? Perhaps Squid cannot resolve
clients.interact.mtel.eu domain name? You can see Squid error response
(that may have more details) in a packet capture (or, probably, in
cache.log after setting debug_options to ALL,2).
Your Squid cannot establish a TCP connection to 188.8.131.52 port 443.
Judging by the timestamps, there was a 60 second timeout somewhere. I do
not know why the connection attempt timed out, but the answer probably
lies outside of Squid itself. FWIW, my Squid can connect to that address.