Incidents happen, that's life. You can hedge your bets, but some things are out of your control. Communicating with your customers however is entirely within your control. Fastmail did a poor job of it. Their status page was useless beyond an initial "we found an issue" and then nothing for almost 11hrs. Their Twitter account was the same story, didn't bother with the Mastodon account at all. Unfortunately they don't seem to realise or recognise that they dropped the ball on this and that goes entirely unaddressed.

I'm also not really charmed with how they try to minimise the importance of the incident by repeating it only affected 3-5% of the customers. That might very well be. But those are real people and real businesses that rely on your services that were unavailable for the whole of the EU workday and a significant part of the US workday. Everyone I know who was affected is a paying customer, none of us have received so much as a communication or apology for it.

For a company that's been on the internet since 1999, the single-homed setup is a little shocking. But fine, it's being addressed. But both the communication during and after the incident don't inspire a ton of confidence.