The MUD has halted talks because of government repression.
“The talks haven’t produced any result up to now,” Capriles said in an interview over a chicken stew in Barlovento, Miranda on May 10. “With the camp raids the government has shown its problem isn’t the barricades, it’s the protest itself.”
I'm not really sure how chicken stew was relevant...meanwhile, the United Nations is now criticizing the Venezuelan government for excessive use of force:
The United Nations human rights office today voiced concern at renewed violence in Venezuela, and at the reported excessive use of force by the authorities in response to protests.
“We unequivocally condemn all violence by all sides in Venezuela. We are particularly concerned at the reported excessive use of force by the authorities in response to protests,” said Mr. Colville.
“We therefore reiterate the High Commissioner’s call to the Government to ensure that people are not penalised for exercising their rights to peaceful assembly and to freedom of expression and for sustained and inclusive, peaceful dialogue based on Venezuela’s human rights obligations,” he said, adding that OHCHR remains available to support efforts to this end.
That came on the heels of the recent Human Rights Watch report. And concern from Amnesty International. The government and its supporters have consistently argued that the government is using restraint in the face of extremely violent protesters. That line is getting more difficult to credibly sustain.
If you look at this purely from a strategic perspective, Nicolás Maduro will likely find it difficult to convince a majority of Venezuelans that the MUD is responsible for the suspension of talks. And given Maduro's gradual approval slide, Venezuelans clearly want some convincing.
Update: Maduro blames pressure from Miami for the talks being suspended.