Why can I call certain destinations with other VoIP apps, but not with My 050?

The My 050 app technical specifications may differ from those of other companies' apps. Therefore you might not be able to use My 050 from your device. Before paying anything into your account, please place a call free of charge to this test number: 050-6868-0001 and record a 10-second message after the beep. The recording will then be played back to you. If you can hear the recording, then the app is ready to be used from your device. Please note that this call is for sound quality test purposes only and does not guarantee similar results at all times. Internet/network conditions may affect the quality of the calls.