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renanrdrigues
Explorer II
May 4, 2026
Question

NTLM authentication does not work with Explicit Proxy

  • May 4, 2026
  • 2 replies
  • 99 views

I have an explicit proxy test configuration with NTLM authentication;

I have the groups configured in the proxy policy, but while I can authenticate on the computer, I can’t browse the web. In the debug log, it shows the error highlighted in the screenshot it’s unable to read the groups but I’ve already verified that communication between my user and the group configured in the proxy policy is working;

I’m stuck; I don’t know how to fix this.


FortiOS 7.4.11

2 replies

RBA
Staff
Staff
May 5, 2026

As per the debug output group query is failing. I would suggest re validating the config. This should assist you with configuration Technical Tip: FortiGate explicit proxy authentication with Kerberos | Community

renanrdrigues
Explorer II
May 7, 2026

I can authenticate using groups only via LDAP, but I can't authenticate using NTLM alone;

Is the only way to avoid the proxy authentication prompt to use NTLM or Kerberos, or can I do it using LDAP alone?

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