Google Translate is blocked globally in your environment but you want to allow access when embedded in other websites.
SSL interception must be enabled. See enabling SSL interception for more information: Explicit SSL-Interception With Self-Signed Certificate
Copy the following CPL code and add it to your Policy file:
define condition allowed_translate
url.substring=element.js
url.substring=cr.googleTranslate.onTranslateElementLoad
url.domain=translate.googleapis.com
url.substring=translate_a
url.substring=gen204
end
<proxy>
url.domain=translate.google.com
condition=!"allowed_translate" deny
For more information on adding CPL to local policy files see: Add CPL to a local policy file on the ProxySG