We are aware of an issue causing pages to load incorrectly for some users and expect a fix soon. Sorry for the inconvenience.
Have you looked into a mail relay like postfix? Perhaps I am not doing it right either but Postfix just relays emails to the actual mail server host without authentication. Have you also looked at this article?
https://www.ptc.com/en/support/article/CS288408?source=search
https://www.ptc.com/en/support/article/CS357173?source=Bloop
