Former Vice President Joe Biden’s 2020 presidential campaign was also once a client of the tech firm whose glitchy app was behind the caucus catastrophe in Iowa that fouled up the reporting of Monday’s results, according to a report.

Shadow Inc. — led by Gerard Niemira, who developed technology for Hillary Clinton’s failed 2016 presidential bid — worked for the campaigns of Biden and Pete Buttigieg, as well as the Nevada and Wisconsin state Democratic parties, the New York Times reported Tuesday, citing campaign filing reports.

The company, which was paid $63,000 by the Iowa Democratic Party for the error-prone smartphone software that was supposed to help in the tallying of election results, was involved with texting technology and digital advertising with the Biden campaign.

Citing an aide to Biden, the newspaper reported that the campaign used Shadow to text voters prior to its May 2019 campaign launch in Philadelphia, but the technology failed to “pass our cybersecurity checklist.”

The campaign dropped Shadow last year.

Before joining Shadow, Niemira was a top official at ACRONYM, a DC-based nonprofit involved in digital advertising campaigns.

ACRONYM’s CEO and co-founder is Tara McGowan, the wife of Michael Halle, who worked for the Clinton campaign and is an adviser for Buttigieg.

Nearly two days after the caucuses, Iowa has so far only released results from 71 percent of the precincts counted.

They show Buttigieg leading with 26.8 percent, followed by Sen. Bernie Sanders at 25.2 percent.

Sen. Elizabeth Warren of Massachusetts is in third with 18.4 percent and Biden fourth with 15.4 percent.