Customers seem to be turned off by slow service at McDonald's — and it's creating a major problem for the fast-food chain.

In a call with investors on Monday, McDonald's CEO Steve Easterbrook acknowledged that speed of service at the fast-food chain has "declined slightly" in the last year.

The average wait time at a McDonald's drive-thru is 208.16 seconds, according to QSR Magazine's 2016 drive-thru study. Ten years ago, average wait time was 167.1, according to QSR's 2006 study — nearly 25% faster.

McDonald's slowing service may be driving Americans away from the chain. The company reported that the chain's US visits dropped 2.1% in 2016, marking the chain's fourth consecutive years of domestic traffic declines.

The fast-food giant has struggled to quickly serve customers as it has added new items to the menu, like all-day breakfast. Easterbrook acknowledged that McDonald's needed to work towards "net simplification," or reducing the complexity of the menu and operations as the chain introduces new items and services.

McDonald's is hoping that new tech can help speed up service. Hollis Johnson

According to Easterbrook, McDonald's recent investments in technology could be the chain's saving grace.

With the roll-out of digital kiosks and table service, Easterbrook said groups with larger orders could "dwell as long as [they] want," instead of taking up cashiers' time and forcing time-crunched customers to wait. Similarly, expanding the test of online and mobile ordering and payment could help speed up service.

However, new technology also creates more complexity at the chain. Just as a menu need simplification, Easterbrook said the company's technology also needs to be simplified — something that could prove to be difficult as McDonald's implements new tech intended to speed up service.