Duckduckgo is not a Browser its a search engine ..which could be the reason for the problem …Maybe this will help you
Search Engine vs Browser
There is a lot of confusion around the two most frequently used buzz words: search engine and browser. Recently, Google conducted an interview on the streets of New York asking people to define a browser. Out of a sample of over 50, only 8 per cent of the people answered with the correct definition of a browser.
A browser is a software program installed on your computer locally. There are many browsers such as Internet Explorer, Firefox, Safari, and Opera, etc. A browser is used to access various websites and web pages. A search engine is also a software program that searches for some particular document when specific keywords are entered. The search engine matches the exact keywords entered against the documents available on the Internet and returns a list of documents in which the keywords were found. Google and Yahoo are the most popular search engines.
Another interesting thing to be noticed is that you use a browser to get a search engine. For example, you open Internet Explorer, Chrome, or Firefox and then type the web address of a search engine such as Google.com, Yahoo.com.
When you open a search engine and enter a few keywords, a program called an indexer reads the documents on the web and creates an index based on the words contained in each document and returns it if the words match the entered keywords. The search engine uses a proprietary algorithm to create its indices in order to return only meaningful results for each query entered by the user.