It is a reverse proxy. This is the cache peer that would be used: cache_peer 10.190.254.85 parent 443 0 no-query login=PASS no-digest originserver ssl ssldomain=*.mydomain.com sslversion=6 name=mainserver Looking at the logs the url that client is trying to access does not get logged so it does not actually get to that stage. The certificate being used is identical and present on both the old and new servers. Some of these client devices can connect and some cannot, and a firmware upgrade on the devices that do not will fix the issue. Unfortunately we cannot do a firmware update remotely so although it does look like a client issue we would prefer to try and find a workaround on the proxy that would allow the client to connect. -- View this message in context: http://squid-web-proxy-cache.1019090.n4.nabble.com/HTTPS-CONNECT-Failing-Squid-3-3-4-tp4665691p4665718.html Sent from the Squid - Users mailing list archive at Nabble.com.