Error on syncing / Syncing doesn't work

Syncing used to work but after November 2017 it broke? Perhaps you've noticed that changes are not flowing between your client and the Fastmail web interface, or your client is reporting errors such as a broken connection.

For full details, read our blog post on changes that were made to calendaring and contact support.

In summary:

We tested that many clients can automatically update themselves when the URL changes, however some clients need to be manually reconfigured.

We recommend: