Safe Search will disable non supported safe search engine domains. You can allow specific search engine through whitelist.
At this time the following search engines are supported in ScoutDNS Forced Safe Search:
As more search engines support domain restrict options, we will seek to add to our system. Other search engines may support a safe search mode, but do so through URL entries which are not supported by DNS.
Selecting Forced Safe Search will also disable all other search engines. If you require an additional search engine for some reason, or are seeing something blocked you need as a result, you can add the desired domain records to your whitelist.