Zero spendable balance

[Edicksonjga]

(Possible bug in Zingolib)

Sometimes the spendable balance on Zingo Mobile is zero even though I have balance available to spend.

I still can't effectively reproduce the steps to make this happen, but the times it has happened is when I come back from having the app in the background and when I'm in the Send tab switching between addresses and a sync process occurs.

Attached is the error that appears when the spendable balance goes to zero:

[juanky201271]

@Edicksonjga this issue is still there? Please confirm that.