The negotiate validation failed. From negotiate response: Dialect: %1 SecurityMode: %2 Capabilities: %3 ServerGuid: %4 From ...

The negotiate validation failed.

From negotiate response:
Dialect: %1
SecurityMode: %2
Capabilities: %3
ServerGuid: %4

From FSCTL_VALIDATE_NEGOTIATE_INFO response:
Dialect: %5
SecurityMode: %6
Capabilities: %7
ServerGuid: %8

Guidance:
The client successfully negotiated SMB dialect, security mode, capabilities and server GUID with the server, but the validation of these values then failed after connecting to a share. This may be due to a "man-in-the-middle" compromise attempt.