You can edit the blocked sites list used for the entire DSP account and additional lists for individual advertisers in the account.
Blocked sites lists define sets of targets to exclude for your placements. Each list can consist of top-level website domains and any level of sub-domains (such as example.com, my.example.com, or my.new.example.com) and mobile app IDs or package names (such as com.example.app123).
Advertiser-level lists override account-level lists.