Migrants Struggle to Get Appointments on Border Patrol App

“We can’t enter, we don’t understand the new system,” complained Wendy Perez Peña, 31, who left Venezuela in March to escape poverty.

Jeison Rodriguez Jesus Salas, 27, shook his head in frustration.

“They haven’t updated it well, they should have updated it better,” he said.

Out of the group of 11, not one had been able to secure an appointment on Thursday.

Elsewhere along the border, under a burning sun in Reynosa, Mexico, across from McAllen, Texas, Osiris Yamilet Ochoa, 20, had been trying repeatedly to secure an appointment through the app.

On Thursday afternoon, she opened it once again and it read, “Wait for an appointment,” in Spanish.

“Everybody is trying to cross to the United States, but we have heard that if you cross before your appointment date, it may be considered illegal crossing and it may hurt our case,” Ms. Ochoa said as she took a break from selling gum in the streets to buy baby milk for her 8-month daughter, Milagros. “I don’t want to risk it. We have been here for three months. We can wait a few more days.”

The Homeland Security secretary, Alejandro Mayorkas, denied that there were any widespread technical glitches with the C.B.P. One app. “We are utilizing it very effectively,” he said on Thursday. The problem, he said, was a lack of staff resources to schedule as many interviews as needed.