Politico Pro requires version 6.2.2, SSL Configuration and the following database stanza definition in config.txt:
AnonymousURL https://static3.politico.com/*
Title Politico (updated 20180515)
MimeFilter text/plain https://subscriber.politicopro.com/pro-api/.* javascript
URL https://subscriber.politicopro.com
DJ politicopro.com
DJ politico.com
Find https:\/\/
Replace https://