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simdoc's avatar
simdoc
Copper Contributor
Mar 17, 2025
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Authentication issues after upgrading to 2019/CU15

After upgrading to Exchange Server 2019 CU15, we started having many authentication issues.  They appear in many forms.  Executing a get powershell command on any virtual directory will fail for the ...
  • simdoc's avatar
    Mar 24, 2025

    I have the fix.  I wanted to wait a few days to make sure it worked before posting it here.  Setting the policy “Network security: LAN Manager authentication level” to “Send NTLMv2 response only" on all Exchange servers appears to have fixed it.  It did not appear to fix it when I had a combination of CU14 and CU15 servers.  I had to upgrade all to CU15 for this to work.

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