This appears to have been borne out by a leaked letter from European Union director-general for education and culture, Martine Reicherts, which says the country is barred as a result of last year's Brexit vote.
A spokesperson for the European Commission's Scotland office confirmed this to The Evening Telegraph.
The city sent off its bid to be named the capital of culture on October 26 with a grand ceremony outside the Caird Hall.
The current capitals are Pafos, Cyprus, and the Danish city of Aarhus.
The bid had been backed by our columnist Lorraine Kelly.
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Paul Russ, chair of the Nottingham 2023 bid, said that "regardless of any outcomes we will work to implement as numerous positive actions" that were planned to take place.
"We want to continue working with our friends in Europe to promote the long-term economic development of our continent, which may include participating in cultural programmes".
Liverpool was the last city in this country to be the European Capital of Culture back in 2008, and Milton Keynes would have been up against Nottingham, Dundee and Leeds this time around.
It's no consolation to those United Kingdom cities, like Leeds, that have spent up to four years finessing their bids - the West Yorkshire city's glitzy official launch took place just weeks ago and £1m has been spent by the public and private sector thus far.
"That opportunity has now been taken away from the bidding cities".
A Belfast City Council spokeswoman said: "We are aware that DCMS is still in discussions with the European Commission and are seeking urgent clarification on the matter".
Tom Watson, Labour's shadow Culture Secretary, said some of the cities had already spent more than £500,000 on their bids and said the UK Government needed to explain how it will prevent the UK from becoming "culturally isolated".
A DCMS spokeswoman said: "The Prime Minister has been clear that while we are leaving the European Union, we are not leaving Europe and this has been welcomed by European Union leaders".
A DCMS spokeswoman said it remained committed to help the five cities realise their cultural ambitions and is in urgent talks with the European Commission.
She added: "While the dust is still to settle on what is a bombshell for all of us, the spirit of the bid remains very much alive and kicking".