Microsoft 365 is back: how to claim service credits for the November outage

Where things stand

Outlook, Teams calendars, Copilot and the rest of the affected services are working again. At 22:00 UK time on 13 November, Microsoft said: "We continue to observe sustained service recovery across the previously affected environments."

Microsoft hasn't formally closed the incident yet. It said that "due to the severity of impact this incident caused, we're monitoring for an extended period", and that it's "monitoring the backlog of email messages accrued during this event to ensure all process successfully before considering the issue resolved." On its public status page, MO1550821 is still listed as "Service degradation". The full timeline is here, and it'll be marked resolved when Microsoft says so.

What to check in your tenant now

• Delayed mail. Mail queued during the outage may still be arriving, possibly out of order. Use message trace in the Exchange admin centre to check for anything that was delayed or bounced, especially mail from customers or suppliers.
• Anything that runs on mail or Graph. Microsoft said Graph requests for mail, calendar and contacts could time out. Check scripts, integrations and flows that read mailboxes, and rerun anything that failed.
• Compliance and security jobs. Purview DLP, auto-labelling and classification were affected. Check for policy actions that didn't run while it was down.
• Your users. A short note saying email is back, that delayed messages may still arrive, and who to contact if something is missing, will save your service desk a lot of calls.

What the SLA promises

Microsoft's Service Level Agreement for Online Services sets an uptime target for each service. For Exchange Online, the service at the centre of this outage, Downtime is "any period of time when users are unable to send or receive email with Outlook Web Access." There's no scheduled downtime for Exchange Online.

Uptime is worked out per tenant, per calendar month, in user minutes: the total minutes in the month multiplied by your number of users, less the minutes each affected user couldn't use the service. If uptime falls below a threshold, you get a credit against that service's fees for the month:

Monthly uptime	Service credit
Below 99.9%	25%
Below 99%	50%
Below 95%	100%

Exchange Online also has separate service levels for email delivery time, guaranteed delivery and accepting or sending mail. The SLA says that if one incident misses more than one service level for the same service, "you must choose only one Service Level under which to make a claim based on the Incident."

Will your tenant qualify?

November has 43,200 minutes. To stay above 99.9%, the average user can only lose about 43 minutes in the month. This outage ran for most of a day.

Say Contoso has 400 users and all of them lost Outlook on the web for 22 hours. That's 1,320 minutes each, out of 43,200, which gives an uptime of about 96.9%. That's below 99%, so Contoso would claim 50% of its Exchange Online fees for November. If only half its users had been affected, uptime would be about 98.5%, which is still a 50% credit. If the outage had hit its users for 6 hours, uptime would be about 99.2%, and the credit would be 25%.

Your own numbers depend on how long your users were affected, which varied by region. Two things to be clear about:

• An incident on the dashboard isn't approval. The SLA says "Microsoft outage communications are intended to help customers take preventive actions for their business-critical applications and are not a confirmation of missed Service Levels or Service Credits eligibility." Microsoft decides whether a credit is owed after you claim.
• Credits cover the affected service only. They apply "only to fees paid for the particular Service, Service Resource, or Service tier for which a Service Level has not been met." Microsoft's partner guidance gives the example of a suite where only SharePoint was down: "the SLA credit is approved only for SharePoint and not the customer's entire plan."

How to claim

How you claim depends on how you bought Microsoft 365.

If you buy directly from Microsoft

The SLA says "you must submit the claim to customer support at Microsoft Corporation." In the Microsoft 365 admin centre, select Help & support, then the Contact Support icon, and choose phone or email. You need to be an admin, and Microsoft's support page notes that "you must have at least one subscription bought through Microsoft to access Microsoft support." Raise the claim as its own request, separate from any technical issues.

If you buy through a CSP partner

Your partner files the claim, not you. Microsoft's Partner Center guidance says "credit requests are accepted only from CSP direct and indirect providers," through a support ticket in Partner Center. The partner needs an email from you asking for the credit, and "the customer email submitted as evidence must come from the domain of the affected tenant." An email from a personal address won't count.

Open licensing

Services bought through Open, Open Value and Open Value Subscription agreements get credits as extra service time, in days, rather than money off.

What to include

The SLA says "failure to provide the required information will result in claims being rejected." Include:

• A detailed description of the incident, with the incident IDs: MO1550821 and EX1550543
• The time and duration of the downtime your users had
• The affected services and resources
• The number and locations of affected users
• A description of the errors users saw
• Your tenant ID, and what you did to try to resolve the problem at the time
• For a partner claim: whether the subscriptions were bought through CSP, and your support ticket details

Gather it now, while it's fresh. Save the MO1550821 text from Service health, export message trace results for the outage window, and keep your service desk tickets and any messages to users. Download the post-incident report when Microsoft publishes it, because Service health only keeps 30 days of history.

The deadline

For services other than Azure, the SLA says "we must receive the claim by the end of the Applicable Period following the month in which the Incident occurred." The outage was in November, so your claim, with all the required information, has to reach Microsoft by 31 December 2026. If you go through a partner, give them time to file it before then.

Microsoft says it will "use commercially reasonable efforts to process claims promptly following an investigation, typically within forty-five (45) days of receipt of the claim." Approved credits are applied to your fees for that service.

What credits don't cover

A service credit is the only compensation the SLA offers. It says "Service Credits are your sole and exclusive remedy for any performance or availability issues," and that they "will not be awarded to compensate for any other forms of loss, including but not limited to lost revenue, operational costs, or any indirect losses." The credit for a service in a month can't be more than what you paid for that service in that month, and you can't simply hold back payment instead of claiming.

For most organisations the credit will be small next to what a day without email cost. It's still worth claiming. Once you've gathered the evidence above, filing it takes very little time.