On August 26, 2021, at ~8:01 am UTC, Microsoft posted a notification (@MSFT365status) which indicated that they were investigating an issue in which user storage limits for OneDrive for Business were lower than expected.
The incident number was OD280960.
On July 30, 2021, at ~6:41 pm UTC, Microsoft announced that they were investigating an issue in which users potentially could be unable to connect to Power Apps.
The service incident number was MO274372. This announcement from Microsoft came just one day after a Microsoft 365 service disruption for users in Germany.
On July 29, 2021, at ~3:35 am UTC, Microsoft announced that they were looking into an issue in which users in Germany potentially could have access issues or degraded experiences for Microsoft 365 services.
The service incident number was MO273940.
On July 2, 2021, at ~9:47 am UTC, Microsoft indicated that they were investigating an issue in which users were experiencing latency or were unable to access multiple Microsoft 365 services.
The incident number was MO266345.
On June 14, 2021, at ~9:09 pm UTC, Microsoft indicated that they were investigating a Microsoft Teams issue impacting PSTN calls, with Australia as the impacted region. The service incident number was TM262155.
On June 11, 2021, at ~3:02 pm UTC, Microsoft began reporting a Microsoft Teams issue in which incoming calls were being sent straight to voicemail.
Approximately an hour later, Microsoft was reporting on issue identification and a remediation effort (rollback) was underway.
On June 10, 2021, at ~10:21 am UTC, Microsoft was reporting a Teams issue impacting North America.
Twitter responses soon followed confirming the impact was global. Users were confirming impacts to EMEA, APAC, and South America.
On May 26, 2021, at ~6:31 am UTC, Microsoft stated they were investigating an Exchange Online issue in which users were unable to forward email. However, the exact geos impacted were not immediately confirmed and Microsoft suggested that the impact could be for any user of Exchange Online.
On May 11, 2021, at ~4:04 pm UTC, Microsoft stated they were investigating an email message visibility issue in Outlook.
Many on Twitter immediately voiced their frustrations. The issue was confirmed to be of global impact and was already causing significant business disruptions.
On May 10, 2021, at ~1:20 pm UTC, Microsoft was reporting that they were investigating several issues, namely an issue as to email flow.
Twitter first responders were quick to confirm significant issues, of varying sorts, impacting varying geos, as to Microsoft 365 / Outlook emails and email quarantining.