The email servers are being upgraded over the weekend starting late on Friday evening to a pair of faster mirrored servers. This won’t affect everyone but during the course of this migration email will appear to have disappeared from in-boxes but this isn’t any cause for concern and is merely a side-effect of the migration process.
No email will be lost; it’s just the final synching process needed to improve the mail-servers for everyone. During the course of the weekend the email should fully re-appear.
New email will be continue to be delivered straight away – older emails will be restored as the sync process progresses. Any security certificate error messages can be safely ignored for the duration of this migration. These will disappear after both servers are finally fully synced
thos is work is completed if there are any issues with your mail please contact support via the normal routes ASAP.