To use a proxy server you will need to set environment variables, these can be system or user level.
There are 2 environment variables which must be set:
HTTPS_PROXY - set to the hostname:port of the proxy server. For example, if your proxy server
is on port 8080 on host proxy_host:
setx HTTPS_PROXY proxy_host:8080
HTTPS_PROXY_CREDENTIALS - the username and password to authenticate you to the proxy
server, in the format user:password. For example, if your username is "joe" and password is
"joes_password":
server, in the format user:password. For example, if your username is "joe" and password is
"joes_password":
setx HTTPS_PROXY_CREDENTIALS joe:joes_password
Note that Discover for ArcGIS Pro activation supports only the BASIC authentication type.