Hi @wilberth_euan
Bit confused re your question, is it only the phone that you're having problems connecting a mouse to or the tablet as well?
''If only the phone'' when you connect the mouse using the OTG adapter, swipe down on the home screen and change the setting from ''Charging this device'' to ''MIDI.''
''If the tablet as well'' have you tried using a different known working compatible OTG cable?