Error on insert data in DB

I use the following code to add data to the database from MQTT:

def sendToDB(topic, payload):
’’‘This function will transmit the given payload to the InfluxDB server’’’

receiveTime=datetime.datetime.utcnow()

jsonData = [
{
    "measurement": str(topic),
    #"time": receiveTime,
    "fields": {
        "value": float(payload)
    }
}
]
#jsonData = json.dumps([jsonD])

print jsonData
try:
    dbConn.write_points(jsonData)
    logging.debug("Wrote " + jsonData + "to InfluxDB.")
except Exception as e:
    try:
        logging.critical("Couldn't write to InfluxDB: " + e.message)
    except TypeError as e2:
        logging.critical("Couldn't write to InfluxDB.")

And recive output likr this:

2018-03-04 17:57:18,963 http://localhost:8086 “POST /write?db=mqtt HTTP/1.1” 204 0
2018-03-04 17:57:18,964 Couldn’t write to InfluxDB: cannot concatenate ‘str’ and ‘list’ objects
2018-03-04 17:57:18,964 Received message: tp_dush_a16.8
[{‘fields’: {‘value’: 16.8}, ‘measurement’: ‘tp_dush_a’}]
2018-03-04 17:57:18,972 http://localhost:8086 “POST /write?db=mqtt HTTP/1.1” 204 0
2018-03-04 17:57:18,973 Couldn’t write to InfluxDB: cannot concatenate ‘str’ and ‘list’ objects

but all the data was inserted into the database!