Retrieve reason of fail substrate rpc call

Question

I would like to know if there is a way for understanding why a rpc call via python substrate-interface is failing.

On my case, I'm using python substrateinterface lib. And in function "submit_extrinsic" I failed on rpc call: author_submitExtrinsic.

I got an exception contain: {'code': 1010, 'message': 'Invalid Transaction', 'data': 'Inability to pay some fees (e.g. account balance too low)'} exception. But because I know the transaction should have been composed from valid fee and amount that shouldn't overflow the user account (exactly amount if to be accurate).

I would like to know if there is a way know exactly what was the parameters that reached to blockchain (or the before at the substrate server), to understand what went wrong when building the transaction. Or if maybe the transaction should not be fail.

thanks :)

Answer 1

exactly amount if to be accurate

If by this you mean you are trying to drain your account to Zero, check ExistenceRequirement and how is the fee withdrawal handled in Substrate using the KeepAlive variant.

Your extrinsic will fail if you attempt to withdraw funds from your account going below the existential deposit.