"The reason you send diplomats out to foreign capitals is to engage personally and share confidences and confidential assessments,“ Mirpuri said. Building and acting on trust is "about the cues and nuances,” that aren't available online, he said. “You can reach a much wider audience [when on video], but you can’t get to that next stage of diplomacy.”

After eight years on the Washington diplomatic circuit, Mirpuri says he can cope with pandemic interruptions, but worries for newcomer counterparts: “A new person can’t broaden their contacts.”

One of those newcomer ambassadors in Washington is Austria's Martin Weiss, who arrived in November 2019. Weiss said that in a time of travel restrictions, video tools have helped him figure out “how our Austrians are doing in California, and who's currently on a cruiseship and where.” But the benefits stop when the discussions get complex.

“You have a very different group-dynamic on a video platform. There isn't the same pressure to compromise you would experience if you were in the same room. It's easier to hide behind your own screen,” Weiss said.

For diplomats from some of the world’s far-flung and poorer countries, virtual conferences have been a lifeline in climate negotiations for more than a decade. But Zoom diplomacy can be just another dividing line between the haves and have-nots: Countries that can’t If your country lacks the funds for elaborate system of embassies or diplomatic travel are likely to have subpar broadband and 5G connections, too.

During a recent virtual meeting of the Warsaw International Mechanism — a U.N. climate initiative — a Sudanese representative was unable to participate because of low bandwidth.

The security of videoconferencing systems is another headache for countries, rich and poor. Zoom has faced a backlash over its privacy standards, prompting warnings against its use from organizations as diverse as the German foreign ministry , U.S. Senate and Taiwanese government.

For some governments, the security issues have been of their own making. Early on in the coronavirus crisis, U.K. Prime Minister Boris Johnson posted a screenshot of “the first ever digital Cabinet” on Twitter, revealing the Zoom meeting ID was 539-544-323.

Taiwan, no stranger to diplomatic isolation, simply banned Zoom last week. Government spokesperson Chen Chi-mai said the decision was a matter of “defending the nation's critical communications infrastructure.”

Julia Reda, a former member of the European Parliament who now works for GFF, a German digital freedom NGO, recommends leaders use Nextcloud or Jitsi, “if you want the content of the conversation to be confidential.” The European Union’s Data Protection Supervisor team uses WebEx and Jabber.

When it comes to technical headaches, the European Union may have the biggest diplomatic challenge of all: shifting thousands of meetings in 24 languages online in a given week.