What does access denied or invalid security token mean in Field Pro?

This article helps customers troubleshoot the Field Pro app error, “Access Denied - You do not have a valid security token,” when connecting to a home standby generator. It explains how to check internet connectivity, verify the displayed serial number, and determine when to contact an Independent Authorized Service Dealer or Generac Customer Support for reliable app connection.

  • Jun 22, 2026
  • Knowledge

Title
What does access denied or invalid security token mean in Field Pro?
URL Name
What-does-access-denied-or-invalid-security-token-mean-in-Field-Pro

Public Answer

'Access Denied - You do not have a valid security token' troubleshooting

Environment

This article applies to customers using the Field Pro app to connect to a home standby generator.

Issue

A customer receives an error when attempting to connect to a generator using this path in the Field Pro app:

Work on a home standby generator > Connect to generator now > Select generator serial number

Troubleshooting

Verify internet connectivity

Confirm that the mobile device running Field Pro has a reliable internet connection.

  • Yes, proceed to Verify the displayed serial number
  • No, move to an area with adequate cellular coverage or connect to a reliable Wi-Fi network, then retry the connection

Verify the displayed serial number

Tap Back and review the serial number displayed for the connection attempt.

  • The serial number displays as FFFFFFFFFF, contact an Independent Authorized Service Dealer (IASD) using the dealer locator
  • The serial number displays correctly, contact Generac Customer Support at 1-888-436-3722 for assistance
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