Standard & Poor, the first agency to say the country is in default, said the government had failed to make $200m payments for global bonds due in 2019 and 2024 within the grace period that expired over the weekend.
Venezuela's state-run oil company PDVSA has also been declared in default by rating agencies Fitch and Moody's.
No solid proposals came out of the meeting but officials said they plan to continue to service obligations.
The ratings agency said it would raise its long-term foreign currency sovereign issuer credit and issue ratings to "CC" if Venezuela solved its default on the overdue coupons and remains timely on other payments before the restructuring is completed.
Under the sanctions, no United States citizen can do business with Venezuelan individuals on the list.
The U.S. measures essentially block the issuing of any new Venezuelan debt, while there are also sanctions on chief negotiators, Vice-President Tareck El Aissami and Economy Minister Simon Zerpa, for drug and corruption charges. Many skip meals or suffer from malnutrition and preventable diseases, due to severe shortages of food and medicine and triple-digit inflation.
The sanctions also impose a ban on U.S. entities buying any new Venezuelan debt issues, complicating the government's debt restructuring plan.
It means Caracas skipped a specific bond payment but remains committed to paying off its global debts.
Industry body ISDA said it would reconvene on Tuesday to discuss whether PDVSA had triggered a credit default event through a late payment of its 2017N bonds.
Bondholders had told Reuters on Monday they had not yet received payments on the 2019 and 2024 bonds but were unconcerned about the delay, which they said was partly due to increased bank vigilance following the US sanctions.
It is the first time in recent years the Venezuela government has exceeded the buffer period on its bonds.
On Sunday, Mr Maduro said in a televised address: "Venezuela will never default, it will never happen".
Last week, as the Caracas talks loomed, investors bought Venezuela's bonds on speculation there might be progress in finding a solution, driving a 1,095 basis-point narrowing in spreads from November 7 through Monday.