Phishing attempt via Teams

This looks like a combination of a Teams re-authentication problem and a possible unwanted external chat or phishing attempt. The supported actions are:

1. Do not accept the chat unless the sender is clearly trusted.
   • In Teams, preview the message and check whether the sender identity looks suspicious.
   • If the sender is not trusted, choose Block.
2. If Teams shows a banner or icon that the account needs attention, re-authenticate only through the normal Teams sign-in flow.
   • Select the banner or sign-in button in Teams.
   • Complete the sign-in steps, including MFA if prompted.
   • If no sign-in window appears, check the system tray for a Teams icon with a red dot or exclamation mark and open it from there.
   • If still nothing appears, quit Teams from the system tray and reopen it.
3. Avoid signing in through suspicious prompts.
   • If a message or prompt looks unusual, do not click links or attachments in suspicious Teams messages.
   • If something appears to come from a known organization, verify it through that organization’s official website or another trusted contact method.
4. Check network and app state.
   • If access is challenged repeatedly, make sure the required network connection is active before launching Teams, such as VPN if the organization requires it.
   • Avoid switching networks while Teams is running.
   • Update Teams from profile picture > Check for updates if Teams is still installed.
5. If the unwanted chat or invitation keeps returning, report it internally and treat it as phishing.
   • If a suspicious message was received in Teams, report it and delete it.
   • If work or school credentials may have been involved, notify IT support.
6. If credentials may have been entered into a suspicious prompt, secure the account immediately.
   • Change passwords on affected accounts.
   • Turn on multifactor authentication for every account that supports it.
   • Write down what was entered and where it happened.
7. If the issue is tied to a work or school Teams account, contact the IT admin.
   • Teams sign-in problems can be caused by domain or Microsoft 365 account issues that require admin help.
   • If a smart card or PIN prompt appears and it is not expected, that can indicate an account or authentication configuration issue that needs admin review.

Because Teams was already uninstalled and the prompts still involve account attention and sign-in behavior across Microsoft apps, the most important immediate step is to avoid accepting the encryption chat, block untrusted senders, and secure the Microsoft account if any credentials were entered.

• Prevent spam or phishing attempts from external chats in Microsoft Teams
• Protect yourself from phishing
• Restore your access to Microsoft Teams Free
• Why am I having trouble signing in to Microsoft Teams?
• Security and Microsoft Teams
• Protect yourself from phishing