Recently we encountered an issue sending an email from one domain, hosted on Office 365 to another domain also hosted on Office 365. The destination email address had an apostrophe e.g. tim.o'reilly@example.org and we were getting the error message. 554 5.4.14 Hop count exceeded …

I've recently survived a migration to Office 365 with relatively few scars and coming out only slightly more cynical, bitter and twisted than I was when I when I started¹.

I remember speaking to a Microsoft sales rep at some conference or other, they said that in Office 365 …