Please check the problem as follows:
(1)   Check the GEO targeting option in "Targeting" tab is set to ON. If it is set then please check whether IP address is within a Geo targeting range. If not then, it will show the 404 error.
(2)   Check the "Device Targeting" option. Make sure the device running the offer should match the device type of your “Device Targeting” settings.
(3)   So, when you set both GEO and Device targeting options, it means both the conditions should be satisfied at the time of running the offer. if not then, it will show the 404 error page.
(4)   If all above settings are ok then, please check if the affiliate status and offer status are valid. If the offer is already expired, Affiliates can’t run the offer and it will show the 404 error page.
(5)   If reason doesn’t belong to any of the above conditions, please contact us.