Last Friday, Office 365 customers in Europe and especially the UK had to stop working as the Microsoft hosting servers stopped working.

When trying to use email online, users only saw an ‘AADSTS90033’ error, and the message: “Service is temporarily unavailable. Please retry later.”

As usual, Microsoft’s communications were mixed.  The company doesn’t want to admit the full extent of a problem because it might affect future sales so their public information is usually delayed and incomplete.

Too often customers are left wondering if the problem is with them or Microsoft.

Server failures happen whether they are individual boxes for a single business or enormous cloud services from Microsoft, Amazon or Google.

The customers complaining the loudest are the ones who put too much trust and reliance on Microsoft’s cloud services without a ‘Plan B’.

Have a Plan B

No matter what email hosting you use, you need a non-cloud option to workaround any problems.

Keep a copy offline

Whether it’s your email store (Inbox, Sent Items etc) or documents in OneDrive / Sharepoint you should have a copy on your computer as well.

Outlook for Windows/Mac can sync entire mailboxes to your computer.  Outlook for Windows defaults to only keeping the recent messages but we strongly recommend changing that to keeping a copy of everything offline.

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Any key OneDrive folders should be synced so they are always available.

Alternative email account

Have another way to send email out.  An alternative email account hosted by a different company (not just another Microsoft hosted option).

Then you can send messages out and keep in touch with the world while the cloud service provider is fixing their problem.