What was supposed to be Donald J. Trump’s triumphant return to a social-media platform central to his presidency was marred by glitches on Monday night, when a livestreamed conversation on X between Mr. Trump and its owner, Elon Musk, was significantly delayed by technical issues.

But once their chat began, 40 minutes after it was scheduled, Mr. Musk’s and Mr. Trump’s newly developed camaraderie was on clear display, with the billionaire tech entrepreneur lobbing softball questions that allowed Mr. Trump to rattle off the talking points that have animated his presidential campaign.

The conversation offered little new information about Mr. Trump’s views. Over the course of more than two hours, Mr. Trump attacked Vice President Kamala Harris, his Democratic opponent, as a “phony” who, along with President Biden, failed to address crossings at the U.S. border with Mexico. He repeated a number of false claims, including that the 2020 election was rigged, the criminal cases against him were a conspiracy by the Biden administration to undermine his candidacy and the leaders of other nations were deliberately sending criminals and “their nonproductive people” to America.

To all of these points, Mr. Musk largely voiced his agreement, offering frequent praise as he proved a sympathetic partner to help amplify Mr. Trump’s views on a social-media platform that once barred him for promoting false claims that promoted political violence. Mr. Musk bought Twitter in 2022 and rebranded it as X last year.

“I’ve not been very political before,” Mr. Musk said toward the end of their chat, describing himself as “moderate, if not moderate, slightly left,” and adding that listeners who categorized themselves that way should back Mr. Trump.

Early in the evening, Mr. Musk — who shares with Mr. Trump a contempt for the mainstream media — was clear that he was not conducting an “adversarial” interview but wanted to help “open-minded, independent voters” simply “catch a vibe.”