Trane ALERT 1 AFC_EH CFG1 ERR Error Identification

All,

Can someone please clarify for me what the Air Handler ALERT 1 AFC_EH CFG1 ERR error means and (if possible) why it is occurring?
[EH CFG1 ERR - Electric heat configuration error, AFC (airflow control) configured for zero stages of indoor heat and received a W call]

My equipment:

Trane 4TWVO -19.25 SEER Variable Speed XV20i Heat Pump (4TWV0048A1000CD)
Trane TAM9 ComfortLink™ and Variable Speed Hyperion (TAM9A0C48V41DAB)
Heater (BAYEAAC10LG1BA)
XL850 thermostat (TCONT850AC52UA)

Thanks

source https://hvac-talk.com/vbb/showthread.php?2226418-Trane-ALERT-1-AFC_EH-CFG1-ERR-Error-Identification&goto=newpost