Typically for this transfer scenario you're likely getting an “Invalid Amount” error because you are attempting to send funds greater than the transaction limit for this Customer account type.
As a reminder, in the sandbox:
- Unverified Customer has a weekly transaction limit of $5,000.
- Personal Verified Customer has a default $5,000 transfer limit per transfer.
- Business Verified Customer has a default $10,000 transfer limit per transfer.
To read more on account types, visit our developer documentation.