serdes-kafka-avro-client error

Hi, i use below command to run example
./serdes-kafka-avro-client -P -b 10.202.8.11:40301 -t testschema -p 1 -r http://localhost:8081 -s testvertica -S '{"type":"record","name""testvertica","namespace":"test","fields":[{"name":"f1","type":"string"},{"name":"f2","type":"string"}]}'

enter:str: {"f1":"value2", "f2":"value3"}

./serdes-kafka-avro-client -C -b 10.202.8.11:40301 -t testschema -p 1 -r http://localhost:8081
show error message:
Failed to read avro value: Cannot read string value: Cannot read string length: Cannot read 1 bytes from memory bufferCannot read string value: Cannot read string length: Cannot read 1 bytes from memory buffer