An error message can appear when you add a Microsoft Exchange account, and the Microsoft sign‑in page automatically authenticates an account that is already active in your browser session. As a result, the authenticated email address does not match the email address you entered in the Account Addition form.

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Why This Happens

Microsoft may reuse existing browser credentials or active sessions, especially if you are already signed in to services such as Outlook, Microsoft 365, or another Microsoft application. As a result, the sign-in process completes with a different account than the one you intended to add.

How to Resolve the Issue

Try one or more of the following solutions:

• Sign out of all Microsoft accounts in your browser, and then retry the account addition process.

• Open an InPrivate or Incognito window to start a fresh browser session, and sign in with the correct Exchange account.

• Use a different browser where no Microsoft account is currently signed in.

• Switch to a different network or proxy if cached authentication continues to persist.

• During authentication, ensure that you sign in with the same email address that you entered in the Account Addition form.

After you authenticate with the correct Microsoft account, the Exchange account is added successfully and the error no longer appears.