HAVANA (AP) ― On an island where most people have no Internet access, the arrival of mobile phone email service was embraced with joy.

Tens of thousands of Cubans began emailing like crazy in March ― for days, until the service started to fail, taking much of Cuba’s already shaky voice and text-messaging mobile service down with it.

The island’s aging cellphone towers became swamped by the new flood of email traffic, creating havoc for anyone trying to use the system. Users had to make eight or nine attempts to successfully send an email. Even voice calls by non-subscribers’ began to drop mid-conversation. Callers sounded like they were phoning from the bottom of the sea. Ordinary text messages arrived days late, or not at all.

Since then, the state telecom monopoly Etecsa has issued a rare apology and the troubles have eased. But problems with the service, dubbed Nauta, offer a rare window into the Internet in Cuba, where the digital age has been achingly slow to spread since arriving in 1996, leaving the country virtually isolated from the world of streaming video, photo-sharing and 4G cellphones. Cuba’s government blames the technological problems on a U.S. embargo that prevents most American businesses from selling products to the Caribbean country. Critics of the government say it deliberately strangles the Internet to halt the spread of dissent. Other observers offer a less political explanation: a government desperate for foreign exchange is investing little in infrastructure improvements while extracting as much revenue as possible from communications services largely paid for by Cubans’ wealthier overseas relatives.

Experts say that last explanation appears to be the primary culprit in the case of Nauta, in which the government tried to open connections with the world but floundered due to apparent poor planning and underinvestment.

“Cuba is extremely broke,” said Larry Press, a professor of information systems and expert on Cuban telecommunications at California State University, Dominguez Hills. “If they had access to tons of capital they would probably expand (Internet service) further.”

About 100,000 people ― around 5 percent of Cuban cellphone users ― had subscribed to the service even though it cost 50 times that of many U.S. data plans.

Radio scriptwriter Lisandra Ayala, 36, stood in line for hours in March outside an Etecsa office, dreaming of zipping emails back and forth with her favorite cousin in Canada. Like many Cubans, she has long had a smartphone ― a status symbol frequently brought in by visiting relatives. She paid $1.50 to sign up for a Nauta contract that was supposed to let her send emails with the ability to attach photos, but not send video or check the Web. Even the price of $1 per megabyte, many times higher than in virtually any developed country, didn’t deter her.