CIUDAD JUÁREZ, Mexico — At the foot of the Paso del Norte International Bridge, a half-dozen young men are hunched over their phones. They're trying to sign up for a coveted appointment for an interview at the U.S. port of entry just across the bridge in El Paso, Texas.

One by one, they look up in disappointment, their screens showing a familiar message: "system error."

"When you log in, the app kicks you out," said Luis Suárez, a 37-year-old from Venezuela, while holding up his phone. "The app opens up at 9 a.m., and at 9:01 you can't register."

For migrants like Suárez, the CBP One app is now the primary authorized portal to seek asylum at the U.S.-Mexico border. U.S. Immigration authorities touted a major overhaul of the app that took effect last week, in response to widespread complaints.

But migrants in Ciudad Juárez say the app is still not working for them. NPR observed several people make repeated, unsuccessful attempts to log on to the app on Thursday.

Back to the beginning after months of waiting

"It's a waste of time," said Suárez, with frustration in his voice, "even now that it's been updated."

"It just sits on the logo," he said in Spanish. "It sends you back to the beginning and when you try again, the appointments are gone. You have to wait until the next day."

Suárez knows this from experience. Since he arrived in Juárez six months ago, he's been trying to get an appointment on the app — with no luck.

Suárez got tired of waiting for the app to work, he said. So, he crossed the border and turned himself in to Border Patrol this week. He was detained for four days, and expelled back to Mexico on Thursday. His eyes are bloodshot from exhaustion. But he's not giving up, he said — he wants to get to the U.S. to find a job that will allow him to support his wife and two children in Venezuela.

CBP says it's working on 'minor issues'

Immigration authorities have been trying to make improvements to the CBP One app. They've increased the number of appointments available from 750 to approximately 1,000 per day border-wide. Those appointments are now made available throughout the day, instead of at one specified time.

"We believe that the changes have been working well," Blas Nuñez-Neto, the assistant secretary for border and immigration policy at the Department of Homeland Security, said during a call with reporters on Friday.

"We fully appreciate that there is strong demand for the thousand slots that will be available every day. And so individuals may need to wait," Nuñez-Neto said.

He added: "As with any kind of new roll out of a process or technology, we do expect that there may be some minor issues along the way, and we've been addressing those as they've been brought to our attention."

Immigration authorities said they've changed the CBP One scheduling system to prioritize migrants who have been waiting the longest for an appointment.

But that's not what migrants in Juárez say they are experiencing.

Weighing whether to cross illegally — again

Carlos Carrillo Zambrano said he's been trying to get an appointment through the app since January without success. Carrillo, 23, is originally from the Venezuelan state of Carabobo.

"We live with rumors from the news, Instagram and TikTok," he said in Spanish, "that the border will open up and Venezuelans will be allowed in — that we'll be welcomed. But it's lies. Even those who make it across are often deported."

Carrillo also grew frustrated with the CBP One app, and joined the group of migrants who turned themselves in to the Border Patrol this week. They were expelled back to Juárez under Title 42, the pandemic border restrictions that expired late Thursday night.

Now that Title 42 has ended, they're afraid to try crossing again because they fear they could be subject to longer detention. People who cross the border illegally could face a five-year ban on reentry into the U.S. under the border policies that are now in place.

For now, they say they'll keep trying the CBP One app.

Scraping together money for a phone when it's a linchpin of asylum

That's not even an option for Denise Hernández, another asylum-seeker from Maracaibo, Venezuela.

She said that she and her husband also surrendered to Border Patrol earlier this week and were expelled. He was returned to Juárez but she was sent to Piedras Negras, nearly 500 miles away.

Hernández said she took a train in Mexico to be reunited with her husband in Juárez, but she was robbed on the way. Thieves took everything, she said, including the only mobile phone the couple owned.

"We have to wait to get another phone and try through the app," she said in Spanish. "Otherwise, we will be turned back again. I'm afraid," she said in a whisper.

Hernández, 52, says she was a political activist in Venezuela and can't go back. Her 22-year-old daughter and 5-year-old grandson made it into the U.S., and she's hoping to join them. But her son-in-law was also expelled, and she doesn't know where he is.

"It's a lot of hardship," said Hernández, "but I'm not blaming anyone, we made our own decisions."

Hernández looks off into the distance, maybe wondering if they made the right choice.

"I would have never imagined [the journey] would be this hard," she lamented. "It's been a lot, and now my family is separated."

Hernández and her husband hope to earn enough money to buy a new phone so that they can try the CBP One app again. For now, they're sleeping in a tent on the street near the Paso del Norte Bridge, with the El Paso skyline clearly visible on the other side of the Rio Grande.