Telecom network operator AT&T will cancel its estimated $100 million contract with the troubled Yahoo Inc.

AT&T is cancelling the contract with Yahoo at a time when rival Verizon is actively pursuing the digital media company for acquisition. The development will be a major setback to Yahoo because the deal with AT&T is almost 15-year old.

AT&T has signed a contract to host its Web and mobile portals to Synacor. The deal moves a major chunk of AT&T’s business away from Yahoo.

“We have agreed to have Synacor manage our att.net portal, AT&T-branded applications, and search,” AT&T said in a statement. Yahoo will continue to host email for AT&T customers.

Synacor said in a statement that the deal, which is to provide portal services for AT&T customers that drive user engagement, will bring nearly $100 million per year, after full product deployment in 2017.

As per the dela, Synacor will develop and manage desktop and mobile portal services, populate these experiences with rich content sourced from popular brands and monetize these experiences through search and advertising.

Synacor CEO Himesh Bhise said: “We are thrilled that AT&T will be using our managed portal services, mobile apps, and advertising solutions in this important initiative to deepen engagement with their customers. We already are developing initial products for deployment in 2016, and have started working on a next-gen product for 2017.”