NodeRed Json to Influxdb

[Colin]

If you just insert one object then it writes data (though not necessarily the way you want it) to the database because, as it says in the node Info
" If msg.payload is an object containing multiple properties, the fields will be written to the measurement."
So it has written each item in the object as a field in the database with the current timestamp. So, using the info from the debug you posted it will have recorded that at that time the field country had the value "USA" and the field cases has the value 215300 and so on. If, for example, you were then to post the next object then it would record that the field country now has the value "Italy" and cases now has the value 110574. The result is that in the database the country has changed from USA to Italy and also the value cases has changed from 215300 to 110574. Note that it assumes that all these are independent. There is no linking between the country and cases at each time. If you want that linkage you will have to understand how influx databases work and in particular understand the difference between fields and tags.
The reason you get the error is because, again from the info tab, the only other ways of passing data are as an array of two objects, which yours isn't , or an array of arrays, which again it isn't.
So, as I indicated before, if you want to use an Influx database then you need to do a bit of research and at least understand the basics of how to use it.