Error: endorsement failure during invoke. response: status:500 message:"error in simulation: failed to execute transaction 83d5de17fa5569456cdd4205808455177bde8953e2b1e4f7c59100c3f76559f0: invalid invocation: chaincode 'CVT' is already initialized but called as init
It sounds like you are submitting a transaction that is flagged as an initialization transaction to a chaincode that has already been initialized. An initialization transaction must only be called once for each deployment of a chaincode.
See the description of initialization in the Approve a chaincode definition for your organization section of this page in the Hyperledger Fabric documentation for a more thorough explanation: