Check your business for single points of failure in 60 seconds
On Thursday 12 November 2026, Microsoft 365 began failing for businesses around the world, and the problems were still being worked on the next day. Microsoft's own advisory listed connection problems across Exchange Online, Teams, SharePoint Online, Copilot and Defender XDR, and the outage tracker Downdetector recorded reports from dozens of countries. Microsoft said it had found no evidence of malicious activity.
For many teams that meant no email, no shared files and, in some cases, no way to sign in to other work apps that use a Microsoft account. The outage itself was out of their hands. How much of the business it took down was not.
The short answer
Most small businesses rent four critical layers from outside companies: email, staff sign-in, DNS (the address book that points your domain at your website and mail) and website hosting. When one company runs two or more of those layers, a single outage at that company stops them all at once. That is a single point of failure, and you can see most of it from public DNS records in under a minute.
Check it in 60 seconds
- Open the free Single Point of Failure Scanner.
- Type your domain, such as example.com, and press Scan.
- Read the banner at the top of the results. If one company runs two or more critical layers, it says so, and it spells out what you would lose if that company goes down.
- Work through the recommendations in order. Most are free changes you can make this week.
The scanner only reads public DNS records: the MX records that say who receives your mail, the SPF and DMARC records that say who may send as you, the name servers that run your DNS, and the records that point to your website. It never logs in anywhere and it does not store your domain.
What a typical result looks like
A business on Microsoft 365 that also bought its domain DNS through Azure will see Microsoft named for email, sign-in and DNS. The impact line reads like this: if Microsoft 365 or Azure goes down, you lose email, calendar and likely Teams, staff sign-in to work apps, and DNS for your domain. That last one matters most, because when DNS fails, your website and email stop resolving even if the website is hosted somewhere else.
Google Workspace customers will usually see Google for both email and sign-in. That pairing is normal and hard to avoid, which is why the next steps focus on the layers you can separate.
The fixes that remove the most risk
- Keep DNS with a different company from your email and website. If one of them fails, you can still point traffic somewhere else.
- Agree a backup way to reach staff and customers. A group text list or a chat tool from another company, and a rule for when to switch to it.
- Publish DMARC. Outages bring phishing emails that pretend to be from you or your suppliers. DMARC tells receiving mail servers to reject mail that fails your checks.
- Write a one-page break-glass plan. Who decides, how staff are told, which emergency admin accounts work without single sign-on, and where the plan lives offline.
- Subscribe to your providers' status pages. The scanner lists the ones it can find.
What the scan cannot see
Public DNS shows a lot, but not everything. It cannot see contracts, backups, private networks or sign-in systems that leave no DNS trace, and a proxy such as Cloudflare can hide the server behind a website. Treat the score as an indicator that tells you where to look, not as an audit.
Run the free scan now, while the outage is fresh, and fix the first item on the list before the next one.
Sources
- Widespread Microsoft outage continues, taking down Outlook and other 365 services, CNBC, 12 Nov 2026
- Microsoft 365 Outage Disrupts Outlook, Exchange Online and Teams, SecurityWeek
- Massive Microsoft 365 outage disrupts Outlook, Teams, Copilot worldwide, BleepingComputer
- Microsoft hit by global outages: What happened and why?, Al Jazeera, 13 Nov 2026