Documents at the Government’s Intellectual Property Office show that a formal "notice of threatened opposition" has been registered to block their plans.
According to The Sun, the opposition was filed by Benjamin Worcester of Victoria, Australia, who is believed to have worked as a doctor in the NHS in London from 2011 to 2014 and studied medicine at University College London.
It is not known why he filed the opposition.
Last June, the royal couple submitted an application to trademark hundreds of products and services under their banner – including a newspaper and a magazine, Express reported.
The royal couple’s application to trademark the items came just days after they announced they had split from Prince William and Kate Middleton’s charity, The Royal Foundation.
According to papers published by the Intellectual Property Office, Harry and Meghan are looking to trademark 100 items under their Sussex Royal brand.
Newspapers and magazines came under the “printed matter” section, which also lists booklets, pamphlets, journals, diaries, calendars, notebooks and newsletters.
But it seems the royal couple’s application, which also lists clothing, campaigning and “social care services” such as counselling, is paving the way for a global Sussex brand.
If accepted, Meghan and Harry would then be allowed to launch many ventures under their banner, including starting their own clothing line or publication.