PSM5003 PM 2.5 sensor sending wrong values

Hi,

My PSM5003 PM 2.5 sensor has been sending values of around 5000 (see code below), which is obviously too high to be realistic. It was working fine at the beginning, so I do not think it is because of a factory defect. The set-up area also respects all the required conditions (i.e. not next to smoke).

Please let me know of any possible solution, I would like to replace the sensor only as a last resort.

Thanks a lot.

Code:
{"@iot.count":18274,"@iot.nextLink":
https://qcml-aq-sta.sensorup.com/v1.0/Datastreams(91)/Observations?$top=100&$skip=100”,
“value”:[{"@iot.id":628533,"@iot.selfLink":
https://qcml-aq-sta.sensorup.com/v1.0/Observations(628533)”,
“phenomenonTime”:“2019-08-01T18:58:40.753Z”,
“resultTime”:null,
“result”:5000

That doesn't look like Arduino code to me, although I know there are a load of new Arduino and Arduino-"like" products, so it's possible there's a new way of doing things.

Is this an Arduino problem?

That looks like a json formatted piece of information. Not programming code.

Yes, it is a json "file". Sorry, I don't know how to call this properly.
I was hoping to get some help because I saw some threads on this forum about sensors similar to mine.
It is not directly an Arduino problem although I am using this Plantower sensor with an Arduino product.