EIP-712 error

gistfile1.txt

E       brownie.exceptions.VirtualMachineError: revert: dev: invalid _signature
E       Trace step 619, program counter 4422:
E         File "contracts/exchange_presale.vy", line 204, in exchange_presale.checkSellerSignature:
E           v: uint256 = convert(slice(_signature, 64, 1), uint256)
E           assert ecrecover(digest, v, r, s) == _sellers_signing_account  # dev: invalid _signature
E           return digest

tests/test_exchange_presale.py:309: VirtualMachineError