So, for testing transfers, I create:
customer1 - OK
customer2 - OK
funding source1 for customer1 - OK
funding source2 for customer2 - OK
Verify both funding sources.
So, all customers and funding sources are verified.
Then I try to create transfer from funding source1 to funding source2 (this is allowed in docs).
But I get “Invalid funding source” and no other description.
How I can emulate transfer from one funding source to other funding source? May be I need to use some special data?