Irtsgbr

Two weeks ago, all our Azure production systems went down, and we received an e-mail from them saying

We’ve disabled your Azure subscription

To protect the security and privacy of your account, we perform
routine audits of all Azure subscriptions. During one of these audits,
we identified suspicious activity in your subscription that violates
the Microsoft Acceptable Use Policy. We’ve disabled your subscription
until the issue can be resolved.

If you believe this is an error, please contact Azure support.

We knew of no problem, and had received no previous warnings, so we contacted support. (We have a Standard support plan, which gets us a fairly quick response, but not necessarily a resolution.) After 11 hours (and many e-mails) everything turned on again and we received a message saying simply

You subscription is enabled.

Microsoft have not answered queries for an explanation as to what this "suspicious activity" was, nor how they resolved the situation and were able to enable our account again. They have not explained why they could provide no information about the cause of the problem for the duration of the problem.

Has anyone else experienced this? How can we avoid it in future?

Having your account suspended or terminated without notice is one of the risks of using a public cloud. It is likely a very low risk (for most organizations) but it won't feel that way when it happens to you!

You mitigate this risk the same way as any other single point of failure. You host your applications across multiple cloud providers, so that the loss of one does not completely stop production.

You probably should also have part of your production environment on premise. This design has its own buzzword, hybrid cloud, and each cloud provider has its own idea of a hybrid cloud solution. You should evaluate these to see which meet your needs or whether you need to build something all your own.