Login lacks connect endpoint permission error

  • Hello experts,

    I'm stumped by an error that a user is reporting, partly because the Windows Security event log seems to show audit success while the user is seeing a login failure.

    They are trying to connect to one of our SQL Server 2016 SP3 servers.

    They see this error:

    They see this error:
    Login failed for user 'domain\user'

    In the SQL Server error log I see these errors:

    Login failed for user 'domain\user'. Reason: Token-based server access validation failed with an infrastructure error. Login lacks connect endpoint permission.
    Error: 18456, Severity: 14, State: 148.
    Error: 18456, Severity: 14, State: 148.

    However, the Windows Security event log shows:

    Log Name:      Security
    Source: Microsoft-Windows-Security-Auditing
    Date: 5/2/2022 3:00:26 PM
    Event ID: 4624
    Task Category: Logon
    Level: Information
    Keywords: Audit Success
    User: N/A
    Computer: [computer]
    Description:
    An account was successfully logged on.

    Subject:
    Security ID:NULL SID
    Account Name:-
    Account Domain:-
    Logon ID:0x0

    Logon Type:3

    Impersonation Level:Impersonation

    New Logon:
    Security ID:domain\user
    Account Name:user
    Account Domain:domain
    Logon ID:
    Logon GUID:{00000000-0000-0000-0000-000000000000}

    I have tried the following:

    Granting CONNECT TO [domain\user]

    Granting CONNECT SQL TO [domain\user]

    GRANT CONNECT ON ENDPOINT::[TSQL Default TCP] TO [domain\user];

    But the user is still reporting the error.

    Can someone help me find out what is happening, why it is happening, and how I can troubleshoot it further?

    I've checked these links that at first I thought would resolve the issue:

    https://docs.microsoft.com/en-us/archive/blogs/psssql/why-do-i-get-the-infrastructure-error-for-login-failures

    https://sqlblog.org/2020/07/28/troubleshooting-error-18456

     

    Thanks for any help.

    -- webrunner

    • This topic was modified 2 years, 6 months ago by  webrunner.

    -------------------
    A SQL query walks into a bar and sees two tables. He walks up to them and asks, "Can I join you?"
    Ref.: http://tkyte.blogspot.com/2009/02/sql-joke.html

  • Thanks for posting your issue and hopefully someone will answer soon.

    This is an automated bump to increase visibility of your question.

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