Verizon Communications Inc. continues to face a slowdown in its core wireless business, putting more pressure on the phone giant to show progress in its plan to transform itself into a media and advertising rival to Facebook and Google.

The nation’s largest wireless carrier sacrificed profits in the fourth quarter by cutting prices and offering giveaways like free iPhones, but lured fewer customers than expected. The company added 591,000 subscribers, compared with 1.5 million a year earlier and the 744,056 projected by analysts. By comparison, T-Mobile US Inc. gained 1.2 million in the period.

As challenges mount in the wireless industry, Verizon is turning the business in a new direction. Using go90, its video-streaming business, AOL’s web properties and possibly Yahoo! Inc., the company is hoping to collect enough web users to challenge Alphabet Inc.’s Google and Facebook Inc. in the mobile video and advertising market.

Those plans are off to a rocky start. Go90 hasn’t been a blockbuster with viewers. The mobile streaming service cut 155 staff late last week, with most affected working out of main go90 office in San Jose.

Meanwhile, Yahoo said Monday the sale of its main web operations to Verizon has been delayed until next quarter to meet closing conditions while the company recovers from the disclosure of massive hacks to its user accounts. Verizon is exploring a price cut or possible exit from the pending acquisition that was valued at $4.83 billion when it was announced in July, a person familiar with the matter said in December.

Shares of Verizon dropped 2.1 percent to $51.30 at 7:53 a.m. in New York Tuesday before the official market open.