(Bloomberg) — A failed fiber-optic link crippled the computer network at the highest level of the Canadian government throughout the day on Jan. 31, but an investigation has found no evidence of deliberate sabotage, a spokesperson said.

The outage, however, hampered the ability of Prime Minister Justin Trudeau’s staff to coordinate ahead of US President Donald Trump’s threat to impose 25% tariffs on Canada on Feb. 1.

Staff in the Prime Minister’s Office and the Privy Council Office were unable to use their work computers to perform even basic tasks such as sending emails or printing documents, according to affected people who spoke to Bloomberg on condition they weren’t named.

Work phones were still operational on the network, so government staffers were reliant on their mobile devices throughout the day, the people said. The outage was fixed just before midnight on Friday, about 24 hours after it began.

“A failed fiber link connection resulted in the outage that occurred,” Nick Wells, a spokesperson for Shared Services Canada, the government’s information technology department, said in an email. He added the department is reviewing the matter with the vendor supplying the fiber-optic link.

“There is no indication this was a result of a cybersecurity event or any other deliberate action,” Wells said.

Staff who spoke to Bloomberg were frustrated that the government’s computer network was apparently so vulnerable that even just one fiber-optic link failure was capable of taking it down for a full day.

They also expressed relief that there was — at least so far — no sign that hostile actors were behind the event.

Trump signed an executive order on Feb. 1 pledging levies of 25% on all Canadian exports to the US except for energy, which would face a lower rate of 10%. The tariffs were to take effect Tuesday, but Trump agreed Monday afternoon to delay them by 30 days after Trudeau promised to expand his border-security plan.