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pannaroy's avatar
pannaroy
Copper Contributor
Apr 12, 2026

MS Office 2024 LTSC- Repeated credential prompts when adding delegated mail box

We are facing issue in MS office 2024 LTSC where primary mailbox works normally but repeated credential prompts when adding delegated mailbox. Outlook opens but keep asking for username/password. MS office 2024 LTSC is installed as On-premises exchange environment. 

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  • Surya_Narayana's avatar
    Surya_Narayana
    MCT
    Apr 13, 2026

    hi pannaroy​  A few quick things to check:

    Don’t add the delegated mailbox manually - remove it and let it auto-map via permissions

    Clear Credential Manager (old cached creds can cause prompt loops)

    Create a new Outlook profile and test

    Verify authentication setup (NTLM/Kerberos mismatch can trigger repeated prompts)

    Confirm user has Full Access (not just folder-level permissions)

    This is usually an auth/config mismatch, and Office 2024 LTSC seems a bit more sensitive to it.