Solved
Login problem when viewing articles
When I am not logged in and view an article, there is the "Please Log In to view the full article" link at the bottom.
When I click this and log in, (Loginpage URL is https://www.ptc.com/en/support/login?returnurl=https://www.ptc.com/en/support/article?source=subscription&n=CS287459, so it contains the article number)
I get a message ""Sorry. Article was not found. Here are some options:".
(The URL here is just https://www.ptc.com/en/support/article?source=subscription)
I use browser>back to get around this, but obviously the redirection is broken somewhere.
Tested with Firefox and Chrome.

