Hi Noel,
Thanks for your question and concern. My name is Josh Wells and I am a support engineer on the Microsoft Dynamics CRM support team.
I have reviewed your situation and I would believe that the issue was due to maintenance of the O365 service. If you are seeing an immediate issue, you can always look at the Service Health Dashboard which will tell you if there is a known issue going on at the moment. To do this, open up your O365 portal and click on Service Health under Support. This will give you a pretty extensive view of what service may be experiencing issues.
If you notice some errors after the fact, you can look at the history of maintenance events or even service issues. To do this, you can click on View history for past 30 days within the Service Health page.
If you are curious of when there is any sort of maintenance being scheduled, you can click on Planned Maintenance and that should give you some advance notice of what is coming up.
If you want to try and stay on top of notifications, there is even an RSS feed you can subscribe too.
I hope this is helpful. If you have any further questions, feel free to let me know.