Facebook should be growing quickly in Africa. After all, it’s a mobile-first continent with some of the fastest growing economies in the world. But there are signs that the social network is not taking hold the way it has in some other emerging markets.

More than 1.7 billion people use Facebook fb each month across the world, but it’s audience in Africa is a small portion of that total. In South Africa, Facebook has 14 million monthly users; in Kenya 5.7 million. The company, which launched its first African office in Johannesburg last year, has been working hard on increasing these numbers.

Recently, though, Facebook’s numbers have been leveling off. In South Africa, for example, growth was 7.5% in 2016 compared to 8% in 2015.

Arthur Goldstuck, managing director of tech research firm World Wide Worx, expects more of the same. “It will continue growing for the next few years, but the growth curve will become increasingly flat,” Goldstuck says, ticking off the factors that Facebook must overcome in Africa. “The major challenges remain the high cost of mobile data, the poor quality of mobile networks in many regions, and the inability of many users to afford smartphones that can make full use of all Facebook’s services.”

Facebook will not be the only major global firm that struggles to sustain its growth as it attempts to reach users in more rural areas of Africa, a continent where less than 30% of the population is connected to the internet. It has, however, been one of the most active when it comes to addressing this issue.

Facebook CEO Mark Zuckerberg, Fortune‘s 2016 Businessperson of the Year, recently visited Africa, demonstrating his commitment to the continent.

One effort Facebook has made is to roll out its Free Basics service, which sees it work with operators to offer free access to basic online services. The aim is to connect people to the internet for the first time, and Facebook claims it has already bought 25 million people online across 53 countries globally.

Other initiatives are also underway, such as Express Wi-Fi, which is designed to help entrepreneurs bring their communities online. Earlier this year Facebook also conducted the first successful test flights of Aquila, the first aircraft designed to beam internet into communities from the sky. The aim is to eventually have a fleet of such planes flying around different regions, each creating a communications radius.

Yet all has not run smoothly. Facebook suffered what Goldstuck calls a “massive blow” to its prestige—and a setback to its progress—with the explosion of the SpaceX Falcon 9 rocket in Florida in September, which was carrying the Amos-6 satellite Mark Zuckerberg had been counting on to help extend African internet access. Zuckerberg said he was “deeply disappointed.”

Free Basics has also come under attack. It was recently banned in Egypt and has been criticized by independent campaigners for conflicting with net neutrality, or the idea that no content or applications should be discriminated against online.

Facebook itself says it supports net neutrality, but others argue that Free Basics contradicts that position because it gives Facebook too much control over access. India outlawed Free Basics for this reason. And Egypt claimed the same rationale earlier in the year, though there have been reports that the real reason Egyptian authorities banned it is that Facebook wouldn’t allow the government to conduct surveillance on its users.

Ephraim Percy Kenyanito, Sub-Saharan Africa policy analyst for nonprofit Access Now, argues that the Free Basics service violates net neutrality, and leaves users vulnerable to attack due to its implementation of secure encryption protocol. “The program positions Facebook as a global gatekeeper for internet connectivity around the world,” he says. “It is our belief that Facebook is improperly defining net neutrality in public statements and building a walled garden in which the world’s poorest people will only be able to access a limited set of insecure websites and services.”

Goldstuck says that because Free Basics faces resistance in a number of countries, the Egyptian ban is unlikely to be an isolated event. Kenyanito agrees, but neither can predict at this point where the company will run into trouble next. Dealing with sometimes mercurial governments is likely to remain an issue for Facebook regardless of whether net neutrality is involved.

Facebook’s task is not made any easier by the fact it is not the only big social media beast vying for users in Africa. WeChat, owned by Chinese firm Tencent, is also making forays on the continent, and has already seen significant uptake in South Africa, where it has over five million users. WeChat is betting big on additional services—such as money transfers and airtime purchases—on top of its social network to encourage further growth, and is closing in on Facebook’s WhatsApp, which has been around much longer, in terms of users.

Goldstuck says the fact that WeChat is only really active in South Africa at this point is positive for Facebook, but it may just be a matter of time before WeChat’s appeal spreads.

The race, therefore, is on. It is one Facebook is determined to win, but the social media giant has a number of significant obstacles to overcome for it to claim Africa.