In 2014 DFDS Seaways closed their Harwich to Esbjerg ferry. This means there are no more passenger ferries from the UK to Scandinavia and so you will need travel via Holland, France or Belgium if you would still like to sail to Denmark.
Alternative Sailings: StenaLine Harwich To Holland DFDS Newcastle to Amsterdam P&O Ferries From Hull
Harwich to Hook of Holland Newcastle to Amsterdam Hull to Rotterdam Hull to Zeebrugge
Harwich to Esbjerg Ferries & Mini Cruise