Thank you for your question and reaching out.
The NPS server may identify the Access-Request packet as a faulty RADIUS message since it was not prepared in accordance with RFC specifications. You must get in touch with fdXtended support.
Please try to put the appropriate Send and Receive strings in place.
Leave the Receive string empty and remove the word "default send string" from the box. The monitor only connects and runs a quick service check if you don't specify both a Send String and a Receive String.
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