The recent ban on Huawei in the United States is primarily because the US government is trying to forestall any possible occurrence that might pose a huge threat to its national security. President Donald Trump has forbidden any US companies from dealing with some companies it has blacklisted. Huawei is one of those companies, and companies like Google have stopped providing their service to Huawei, a development that might affect the company (Huawei) in the long run. With this development, Huawei users are now being restricted from getting different services from Google, though already existing Huawei smartphones are not affected in any way.
The trade war between China and the United States is another reason for Huawei's ban, although the US government is so clever to give security concern as the reason for their actions. Presently, Huawei is still the second-largest manufacturer of smartphones. This actually speaks volumes of the reason why the United States government is dealing with them.
There are two things that are normally being discussed as to why Trump decided to ban Huawei phones. The first reason is that they are considered to be a security threat. The second reason is that there are some trade wars that are ongoing between the United States and China at that time. They were not in good terms then, which caused the ban to take place.
At the time of the ban, Huawei was in second place as the highest-selling phone globally. Some people are saying that Trump is a bit concerned that it will take over the sales of Apple, which is a US brand. There are some Huawei phones that have been released without the usual Android OS, as using Android has also been banned.