Amid all the Trump-Russia conspiracy stories — such as prostitutes in Moscow, a secret trip to Prague and hush money to computer hackers — Democrats seem to have lost interest in at least one of them.

The past two weeks of Michael Cohen’s public testimony and the House Judiciary Committee’s demands for documents contained no inquiries about the elusive Trump computer server. The machine supposedly linked Trump Tower directly to Russia’s largest commercial bank, Alfa, and its oligarch partners.

When it initially surfaced during the campaign, the tale added up to Trump-Moscow election collusion.

The theory was pushed by liberal Twitter users based on some IP address numbers and a Trump domain name. Fusion GPS co-founder Glenn R. Simpson, the orchestrator of the Christopher Steele dossier, tried to sell the server conspiracy to then-Associate Deputy Attorney General Bruce Ohr in December 2016, according to Mr. Ohr’s notes. An agent working on behalf of Hillary Clinton presented it to the FBI high command in September 2016.

The New York Times knocked down the story on Oct. 31, 2016, but the liberal Slate news website promulgated the tale that same day.

It has refused to die on other liberal sites. The New Yorker in October published a long piece quoting a cybersecurity specialist identified as “Max” arguing that such a server existed. The New Yorker story triggered a new spat of Alfa Bank allegations at The Atlantic, HuffPost, MSNBC and other liberal outlets.

On March 4, House Judiciary Committee Chairman Jerrold Nadler, New York Democrat, released 81 letters to Trump-connected people and entities demanding any documents on pardon offers, foreign emoluments, the Russian hotel project and the infamous June 2016 Trump Tower meeting between Trump campaign officials and a Russian lawyer.

A Washington Times examination found that no letter mentions Alfa Bank or a server even though letters went to the Justice Department, the FBI and Trump Tower employees — sources who would have the details if such a server ever existed.

Mr. Nadler also sent document-request letters to Mr. Trump’s inner sanctum at Trump Tower: His sons Donald Jr. and Eric, who run the Trump Organization; Executive Vice President Ronald C. Lieberman; bodyguard Matthew Calamari; and personal secretary Rhona Graff.

Cohen, Mr. Trump’s former personal attorney who has turned against his ex-boss and called him a con man, testified Feb. 27 before the House Oversight and Reform Committee. Democrats asked him a number of questions about various Russia conspiracy stories — but not about Alfa Bank.

Said a Republican Capitol Hill source: “They probably figure that the Alfa Bank story has been definitely debunked by now, with multiple forensics experts finding nothing suspicious, plus evidence that Glenn Simpson was pushing this story. So they just move on to the next conspiracy theory.”

When Slate posted the story about an Alfa Bank server on Oct. 31, 2016, a week before the presidential election, Mrs. Clinton immediately struck on Twitter, accusing Mr. Trump of being in bed with Russia.

Cybersecurity specialist Robert Graham analyzed the various codes and addresses and concluded that the Trump-related IP address and server were controlled by a marketing firm, not the Trump Organization.

‘This is nonsense,” Mr. Graham blogged. “The evidence available on the Internet is that Trump neither (directly) controls the domain ‘trump-email.com,’ nor has access to the server. Instead, the domain was set up and controlled by Cendyn, a company that does marketing/promotions for hotels, including many of Trump’s hotels. Cendyn outsources the email portions of its campaigns to a company called Listrak, which actually owns/operates the physical server in a data center in Philadelphia.

“In other words, trump-email.com is not intended as a normal email server you and I are familiar with, but as a server used for marketing/promotional campaigns,” he wrote.

Cohen has told Congress that he has no knowledge of a Trump Tower-Alfa Bank server.

In a 2017 interview with The Washington Times, Cohen referred to it as a “third-party server.” He said Alfa Bank employees apparently stayed at Trump hotels and that their names were added to a mass email list used by the spam server.

Democrats also are shying away from Mr. Steele’s dossier, which became the fodder of liberal Trump accusers when it hit public consciousness on BuzzFeed’s website in January 2017.

Mr. Steele wrote that Cohen secretly traveled to Prague in August 2016 to meet with operatives of Russian President Vladimir Putin and pay hush money to computer hackers.

No public evidence has arisen. Special counsel Robert Mueller hasn’t charged Cohen with any type of Russian conspiracy. Cohen repeatedly has denied the trip happened.

Also, there has been no public confirmation that Mr. Trump frolicked with prostitutes in Moscow, as Mr. Steele’s Russian sources alleged.

Fusion’s Mr. Simpson has pushed the Prague theory as well as the Alfa Bank story. Months after raising the allegation to the Justice Department, Mr. Simpson told the Senate Judiciary Committee that he had no opinion.

He was not the only Clinton operative to try to sell the Justice Department on Alfa Bank. Michael Sussmann, a partner in the Clinton campaign’s law firm, Perkins Coie, pitched the server story in September 2016 to James Baker, then the FBI general counsel.

In the two years since the Slate story and the New Yorker piece, journalists don’t appear to have made progress nailing it down.

The 2016 Slate headline: “Was a Trump Server Communicating With Russia?”

The 2018 New Yorker headline: “Was There a Connection Between a Russian Bank and the Trump Campaign?”