I get those CPAN urls OK. It looks like the issue is only with HTTPS sites. I have HTTP_PROXY and HTTPS_PROXY set including user/pass details in the form HTTP_PROXY='http://user:pass@proxy.my.net:8080'
me@linuxbox:~> lwp-request -m get -USsed http://ppm.activestate.com/C
+PAN/authors http://cpan.perl.org/authors?
GET http://ppm.activestate.com/CPAN/authors/
User-Agent: lwp-request/5.810
GET http://ppm.activestate.com/CPAN/authors --> 301 Moved Permanently
GET http://ppm.activestate.com/CPAN/authors/ --> 200 OK
Cache-Control: proxy-revalidate
Connection: close
Date: Fri, 27 Jan 2017 16:11:05 GMT
Age: 0
Server: Apache
Content-Length: 4728
Content-Type: text/html;charset=UTF-8
Client-Date: Fri, 27 Jan 2017 16:11:53 GMT
Client-Peer: 10.244.0.50:83
Client-Response-Num: 1
Title: Index of /CPAN/authors
GET http://www.cpan.org/authors/?
User-Agent: lwp-request/5.810
GET http://cpan.perl.org/authors? --> 301 Moved Permanently
GET http://www.cpan.org/authors? --> 301 Moved Permanently
GET http://www.cpan.org/authors/? --> 200 OK
Cache-Control: proxy-revalidate
Connection: close
Date: Fri, 27 Jan 2017 16:11:54 GMT
Via: 1.1 varnish-v4
Via: 1.1 varnish
Via: 1.1 varnish
Accept-Ranges: bytes
Age: 0
Server: Apache/2.2.15 (CentOS)
Vary: Accept-Encoding
Content-Length: 4722
Content-Type: text/html;charset=UTF-8
Client-Date: Fri, 27 Jan 2017 16:11:54 GMT
Client-Peer: 10.244.0.50:83
Client-Response-Num: 1
Fastly-Debug-Digest: 492dd663e1697be6e60aeecd19b5bf028765c1b3d66167d36
+df53fb8eefe26c0
Title: Index of /authors
X-Cache: MISS, MISS
X-Cache-Hits: 0, 0
X-Served-By: cache-lax8636-LAX, cache-bma7023-BMA
X-Timer: S1485533514.441262,VS0,VE504
Now if I go for https://google.com
me@linuxbox:~> lwp-request -m get -USsed https://google.com
GET https://google.com
User-Agent: lwp-request/5.810
GET https://google.com --> 400 Bad Request
Cache-Control: no-cache
Connection: close
Pragma: no-cache
Content-Length: 677
Content-Type: text/html; charset=utf-8
Client-Date: Fri, 27 Jan 2017 16:16:23 GMT
Client-Peer: 10.244.0.50:83
Client-Response-Num: 1
Proxy-Connection: close
Title: Request Error
At this site I have the same proxt settings for http and https, which strikes me as odd, but works fine on my windows lappy.
Cheers,
R.
Pereant, qui ante nos nostra dixerunt!