Microsoft issues workaround after Teams “Couldn’t Connect” error

Microsoft has rolled out a workaround after a recent sidebar update caused widespread “Couldn’t connect to this app” errors in Teams, disrupting access for some of its users.

What happened

A widespread issue recently impacted users of Microsoft Teams, where launching the desktop or web app triggered an error stating, “We couldn’t connect to this app.” The disruption hindered access for affected individuals and organizations. Microsoft confirmed that the issue stems from a recent sidebar update, which inadvertently triggered a problematic code path, causing launch failures across organizations globally. 

Going deeper 

Microsoft categorized the incident as an advisory-level issue, meaning that while functionality was impaired, the underlying services remained operational. The root cause, a sidebar UI change, was not intended to disrupt connectivity but did so for many users. The company launched a phased rollout of a fix, with approximately 25% of affected customers already restored, and expects full remediation by August 21st, 2025, as per its communications timeline.

What was said

According to UC Today, Microsoft’s service alert outlined the situation clearly, stating “Affected users see an error that ‘We couldn’t connect to this app’ when launching the Microsoft Teams desktop and web apps ...” To help users keep using Teams during the outage, Microsoft advised a workaround, “Instead of launching Teams normally, affected users can successfully access the platform by clicking directly on the ‘Activity’ or ‘Chat’ buttons on the left sidebar...”

Why it matters

“In Microsoft’s FY24 Q1 results, they disclosed that the Teams number of users had reached 320 million monthly active users. That’s 80% of the overall number for Office 365 monthly active users, ” says Tony Redmond from Microsoft.

With such a vast share of Office 365’s user base relying on Teams, even small disruptions can have outsized effects.

See also: HIPAA Compliant Email: The Definitive Guide (2025 Update)

FAQS

What is an “advisory-level issue”?

Microsoft uses severity classifications for service incidents. An advisory-level issue means that while users are experiencing problems, the core service is still running, and the disruption is not classified as a full outage.

What should I do if Teams isn’t working?

Users can try restarting the app, checking their internet connection, or logging in via the web version. If the issue persists, IT admins should check the Microsoft 365 Service Health Dashboard for advisories.

Does Microsoft provide alternatives during outages?

Microsoft typically issues workarounds when possible, like in this case where users could still access Teams through sidebar buttons while the permanent fix was being deployed.