Voipbuster no credit

I am using VoIP Buster to make calls via asterisk, a few weeks ago I used up my credit and yesterday I bought another credit in other to make calls, Whenever I call-out using asterisk It says "Your credit is too low to complete this call. When I call using VoIP Buster client the calls goes through, Does anyone have idea on how I can fix this problem?

Thanks for your help.