Please check and make sure if the Network's Postback URL in advertiser's system is set properly and is correct. Also check whether the parameters after equal sign have been replaced by Advertiser's parameters.
The picture as below:(PS: huaying is the NetworkID)

For Example: the parameter that advertiser system supplies to affiliate is aff_sub={AFF_SUB}.
(1)   It is set as aff_sub={TID} in Advertiser system and will be added to the offer URL.
(2)   Thenetwork Postback URL will be modified as:{aff_sub}