Environment:
Clients Affected: Microsoft Teams (Desktop for Mac), Teams Web App, and Outlook Web
Account Type: Office 365 / Exchange Online
Issue Description: I am repeatedly unable to create new calendar events or meetings. When attempting to save an event, I receive a popup error stating: "Something went wrong. We couldn't send your calendar event. Waiting a bit might help. Keep your calendar event open to try again later." Signing out and signing back into the application temporarily resolves the issue, but the error consistently returns after a short period.
Key Scenarios & Symptoms:
- Cross-Platform Failure: The exact same error occurs on the macOS desktop app AND when using the web browser versions of Teams and Outlook.
Persistence: The issue persists even after comprehensive local cache and credential clearing.
Troubleshooting Steps Already Taken: To isolate the issue, I have already completed the following steps with no permanent success:
App Reinstallation: Uninstalled and reinstalled the Microsoft Teams application on macOS.
Deep Cache Clear (macOS): Completely removed local cache directories via Terminal (~/Library/Group Containers/UBF8T346G9.com.microsoft.teams, ~/Library/Containers/com.microsoft.teams2, and Classic Teams App Support folders).
Credential Purge: Deleted all Microsoft Teams, ADAL (Active Directory Authentication Library), and Microsoft Office credential entries from the macOS Keychain.
Web Isolation Test: Verified the issue occurs on teams.microsoft.com and outlook.office.com, ruling out a localized macOS client or OS cache corruption.
Time Zone & Regional Sync: Verified that the macOS System Date & Time settings (Time Zone and 12h/24h formatting) exactly match the Time Zone and Regional settings configured in the Outlook Web App (OWA) settings.
- Work Hours Reset: Toggled and re-saved the "Work hours and location" in OWA to force an update to the server parameters.
- One Account Issue across organization: Only one account is facing this issue across the entire organization.
Request: Given that this issue occurs consistently across the desktop application and the web browser, 
could you please help identify what is causing this bug and provide the appropriate solutions to resolve it?