Android Question Firebase Error Code: 0

[catyinwong]

LoadAd function of the NativeExpressAd returns the error code "failed: 0"

May I know what it means?

 

[Erel]

Does regular banner ads work?

 

[catyinwong]

Tried. Regular banner ads also returns error code: 0

 

[Erel]

Are you testing it on a real device?
Make sure that the ad unit id is correct.