I spent a whole day at work last week doing meetings and discussing various options we had to try to avoid an annoying "feature" of Outlook. Paying customers of Office 365 can get a thing called "advanced threat protection" where every link in email is changed, so when you click you get to a Microsoft server that first opens your link in a sandbox before redirecting you. That breaks confirmation emails or "magic link" authentications because this "virtual click" causes links to expire, and it was interesting to look at all the ways other people in open source projects have tried to fix this. Ghost adds a 10 second timeout after the first access to the link where you can still click to login, some other projects detect the IP of that specific server to redirect it somewhere else, etc.