Transaction

[Error Code: 1101] error caused by: 1 error occurred:
	* transaction invocation failed when executing transaction: [Error Code: 1101] cadence runtime error: Execution failed:
error: unexpectedly found nil while forcing an Optional value
  --> 5ba16929557493ebd7b1f214859a0e71492cd4908657b87eb1af9dfa3878564d:23:19
   |
23 |     let vaultRef = signer.borrow<&FungibleToken.Vault>(from: StoragePath(identifier: "USDCVault")!)!
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^