Time Warner’s streaming service, HBO Now, has gotten off to a slow start and is falling short of analyst expectations, The Post has learned.

HBO Now, the media giant’s first step outside the cable universe, launched in April and, at year’s end, had 800,000 to 1 million paying subscribers, according to two pay-TV insiders.

Time Warner, which reported fourth-quarter results Wednesday, confirmed The Post’s exclusive report when it divulged HBO Now numbers for the first time. HBO CEO Richard Plepler pegged the subscriber count at 800,000 in a call with analysts.

Wall Street had forecast 1 million to 2 million subscribers.

For $14.99 a month, HBO Now lets viewers see HBO without a cable subscription.

Netflix reported last month it had more than 75 million subscribers. Dish Network’s Sling TV, launched in February 2015, as of November reported nearly 400,000 subscribers.

The somewhat slower-than-expected start could be the result of the timing of “Games of Thrones” seasonal run. Season 5 ended last June and Season 6 doesn’t begin until April 25. Fans of the series could be waiting until the new season to jump into HBO’s pay streaming app.

Also, subscriber numbers may reflect that the app only launched in April and, for the first three months, was only available on Apple TV.

Time Warner shares on Tuesday fell 6.2 percent, to $63.11, wiping out all the gains logged in 2016. The shares had a nice run up in early 2016 amid talk that activist shareholders has purchased shares and could start rattling the cage of Chief Executive Jeff Bewkes.

HBO declined to comment.