When a bypass list for the required URLs is installed as the following, the connection problem is resolved.
;:::::::::::::::::::::::: MS Learning Lab Bypass Script :::::::::::::::::::::::::::::
<proxy>
condition=ByPassProxyByURL http.client.persistence(no) http.server.persistence(no) bypass_cache(yes) authenticate(no) detect_protocol(none) http.request.version(1.0) http.response.version(1.0) server_url.dns_lookup(ipv4-only)
<cache>
condition=ByPassProxyByURL pipeline(no) cache(no) request.icap_service(no) response.icap_service(no)
<ssl-intercept>
condition=ByPassProxyByURL ssl.forward_proxy(no)
define condition ByPassProxyByURL
url.domain="labondemand.com"
url.domain="holsystems.com"
url.domain="mslearningcampus.com"
end condition ByPassProxyByURL
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