Motorola Moto X (2014) — App does't work on my phone

Hi,
Good day. I am Sriram from Nairobi, Kenya. I own a Moto X Play XT1562 model. I bought this phone in Dubai in February 2016. It's a great phone and working fine. I have an issue now. We have developed an app for hailing taxis. While testing the app, i installed the APK directly and it was working fine. Then when we went live a couple of days back, I could not download the app from the app store - I was getting a message saying this app is not available for your country. I checked the countries list on the developer portal and it is available for Kenya (Kenya only). The I tried clearing the data and cache memory and now i am able to download the app, but I am unable to login and use the app. I found this issue happening in a couple of other devices as well (samsung J7 and note3). The common thing among these devices is that they were bought outside Kenya. Could that be the reason for the app not to work? But all other apps are working fine. Pl let me know how to address this issue. Thanks in advance.
Regards
Sriram