Device Discovery cannot find DigiOne IAP

Device discovery cannot find my DigiOne IAP device.
When powered and ethernet cable is connected the LINK led is off.
The LEDS on are Power, RTS, DTR
The DIAG LED is steady blinking
The TX LED is blinking
What am I missing?

Link LED off, sounds like the Ethernet auto-negotiation is not working between the Digi One IAP and your switch. Make sure to set both sides to “auto” or both sides to “fixed 100MBit” e.g.

The following is a useful link when having issues discovering a Digi One, Portserver TS, and other Digi devices which use the Digi Device Discovery Prototocol (ADDP):