Likely it is due to violating US sanctions on sales to Iran. https://www.forbes.com/sites/kenrapoza/2019/01/08/further-investigations-show-chinas-huawei-broke-

Likely it is due to violating US sanctions on sales to Iran. https://www.forbes.com/sites/kenrapoza/2019/01/08/further-investigations-show-chinas-huawei-broke-iran-sanctions/ https://www.forbes.com/sites/kenrapoza/2019/01/08/further-in... For comparison, that is what ZTE was accused of as well and received very similar treatment by the US. https://www.scmp.com/business/companies/article/2142002/us-slaps-zte-seven-year-components-ban-breaching-terms-sanctions https://www.scmp.com/business/companies/article/2142002/us-s...