Hours before sunrise, migrants at one of Mexico’s largest shelters wake up and go online, hoping to secure an appointment to try to seek asylum in the U.S. The daily ritual resembles a race for concert tickets when online sales begin for a major act, as about 100 people glide their thumbs over phone screens.

New appointments are available each day at 6 a.m., but migrants find themselves stymied by error messages from the U.S. government's CBPOne mobile app that's been overloaded since the Biden administration introduced it Jan. 12.

Many can’t log in; others are able to enter their information and select a date, only to have the screen freeze at final confirmation. Some get a message saying they must be near a U.S. crossing, despite being in Mexico’s largest border city.

At Embajadores de Jesus in Tijuana, only two of more than 1,000 migrants got appointments in the first two weeks, says director Gustavo Banda.

“We're going to continue trying, but it's a failure for us,” Erlin Rodriguez of Honduras said after another fruitless run at an appointment for him, his wife and their two children one Sunday before dawn. “There's no hope.”

Mareni Montiel of Mexico was elated to select a date and time for her two children — then didn't get a confirmation code. “Now I'm back to zero,” said Montiel, 32, who has been waiting four months at the shelter, where the sound of roosters fill the crisp morning air at the end of a rough, dirt road.

CBPOne replaced an opaque patchwork of exemptions to a public health order known as Title 42 under which the U.S. government has denied migrants’ rights to claim asylum since March 2020. People who have come from other countries find themselves in Mexico waiting for an exemption or policy change — unless they try to cross illegally into the U.S.

If it succeeds, CBPOne could be used by asylum-seekers even if Title 42 is lifted as a safe, orderly alternative to illegal entry, which reached the highest level ever recorded in the U.S. in December. It could also discourage large camps on Mexico's side of the border, where migrants cling to unrealistic hopes.

But a range of complaints have surfaced:

— Applications are available in English and Spanish only, languages many of the migrants don't speak. Guerline Jozef, executive director of the Haitian Bridge Alliance, said authorities failed to take "the most basic fact into account: the national language of Haiti is Haitian Creole.” U.S. Customs and Border Protection says it plans a Creole version in February; it has not announced other languages.

— Some migrants, particularly with darker skin, say the app is rejecting required photos, blocking or delaying applications. CBP says it is aware of some technical issues, especially when new appointments are made available, but that users’ phones may also contribute. It says a live photo is required for each login as a security measure.

The issue has hit Haitians hardest, said Felicia Rangel-Samponaro, director of The Sidewalk School, which assists migrants in Reynosa and Matamoros, across from Texas' Rio Grande Valley. Previously, about 80% of migrants admitted to seek asylum in the area were Haitian, Rangel-Samponaro said. On Friday, she counted 10 Black people among 270 admitted in Matamoros.

“We brought construction lights pointed at your face,” she said. “Those pictures were still not able to go through. ... They can't get past the picture part.”

— A requirement that migrants apply in northern and central Mexico doesn't always work. CBP notes the app won't work right if the locator function is switched off. It's also trying to determine if signals are bouncing off U.S. phone towers.

But not only is the app failing to recognize that some people are at the border, applicants outside the region have been able to circumvent the location requirement by using virtual private networks. The agency said it has found a fix for that and is updating the system.

— Some advocates are disappointed that there is no explicit special consideration for LGBTQ applicants. Migrants are asked if they have a physical or mental illness, disability, pregnancy, lack housing, face a threat of harm, or are under 21 years old or over 70.

Still, LGBTQ migrants are not disqualified. At Casa de Luz, a Tijuana shelter for about 50 LGBTQ migrants, four quickly got appointments. A transgender woman from El Salvador said she didn't check any boxes when asked about specific vulnerabilities.

The U.S. began blocking asylum-seekers under President Donald Trump on the grounds of preventing the spread of COVID-19, though Title 42 is not applied uniformly and many deemed vulnerable are exempted.

Starting in President Joe Biden’s first year in office until last week, CBP arranged exemptions through advocates, churches, attorneys and migrant shelters, without publicly identifying them or saying how many slots were available. The arrangement prompted allegations of favoritism and corruption. In December, CBP severed ties with one group that was charging Russians.

For CBPOne to work, enough people must get appointments to discourage crossing the border illegally, said Leon Fresco, an immigration attorney and former aide to Senate Majority Leader Chuck Schumer, a Democrat.

“If these appointments start dragging out to two or three or four months, it's going to be much harder to keep it going,” he said. “If people aren’t getting through, they won’t use the program.”

CBP, which schedules appointments up to two weeks out, declines to say how many people are getting in. But Enrique Lucero, director of migrant affairs for the city of Tijuana, said U.S. authorities are accepting 200 daily in San Diego, the largest border crossing. That's about the same as the previous system but well below the number of Ukrainians processed after Russia's invasion last year.

Josue Miranda, 30, has been staying at Embajadores de Jesus for five months and prefers the old system of working through advocacy groups. The shelter compiled an internal waiting list that moved slowly but allowed him to know where he stood. Banda, the shelter director, said 100 were getting selected every week.

Miranda packed his suitcases for him, his wife and their three children, believing his turn was imminent until the new online portal was introduced. Now, the Salvadoran migrant has no idea when, or if, his chance will come. Still, he plans to keep trying through CBPOne.

“The problem is that the system is saturated and it's chaos," he said after another morning of failed attempts.