Outage in Microsoft 365
Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
Minor
September 25, 2026 - Started 2 days ago
Incident Report
Title: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
User impact: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
Components affected
Exchange OnlineTrusted by 1,000+ teams
The Status Page Aggregator with Early Outage Detection
Stop finding out about outages from your users. Monitor 6,320+ cloud services and get alerted the second something breaks.
Latest Updates ( sorted recent to last )
1 day ago - at 09/26/2026 12:24AM
Title: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
More info: As a temporary alternative, impacted users may reply or reply all to email messages through user inboxes.
Current status: We've completed the validation of our planned fixes and are completing the final stages to prepare them for deployment. We anticipate that users will see progressive relief beginning Monday, September 28, 2026, up to our planned remediation date of Friday, October 2, 2026.
Scope of impact: This issue impacts any user attempting to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online. This information may be updated as our investigation continues.
Next update by: Tuesday, September 29, 2026, at 1:00 AM UTC
1 day ago - at 09/25/2026 10:33PM
Title: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
More info: As a temporary alternative, impacted users may reply or reply all to email messages through user inboxes.
Current status: We're conducting verification and validation testing on our proposed remediation to ensure that it will safely and effectively remediate this issue.
Scope of impact: This issue impacts any user attempting to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online. This information may be updated as our investigation continues.
Next update by: Saturday, September 26, 2026, at 12:30 AM UTC
1 day ago - at 09/25/2026 08:57PM
Title: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users may be unable to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
More info: As a temporary alternative, impacted users may reply or reply all to email messages through user inboxes.
Current status: We've identified a recent code change which we believe may be responsible for this issue and are developing a targeted fix to verify.
Scope of impact: This issue impacts any user attempting to reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
Next update by: Friday, September 25, 2026, at 11:00 PM UTC
2 days ago - at 09/25/2026 04:22PM
Title: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
Current status: We're reviewing support case details to better understand the impact scenario and determine our next steps.
Scope of impact: Your organization is impacted by this event and all users attempting to reply to email messages sent to Microsoft 365 groups are affected.
Next update by: Friday, September 25, 2026, at 6:00 PM UTC
2 days ago - at 09/25/2026 03:56PM
Title: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online
User impact: Users can't reply or reply-all to email messages sent to Microsoft 365 groups in Exchange Online.
Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.
Latest Microsoft 365 outages
Some users may experience unexpected application crashes for Microsoft Teams on MacOS devices - 9 days ago
Some users of HP DirectConnect mode on Poly Microsoft Teams Rooms on Android (MTRA) devices may experience call drops - 9 days ago
The Status Page Aggregator with Early Outage Detection
With IsDown, you can monitor all your critical services' official status pages from one centralized dashboard and receive instant alerts the moment an outage is detected. Say goodbye to constantly checking multiple sites for updates and stay ahead of outages with IsDown.
Start free trialNo credit card required · Cancel anytime · 6320 services available
Integrations with
