Http post json to thingspeak from Arduino using GPRS via GSM module

I need to send bulk data from my arduino device via Quectel M66 GSM module. I succedded sending data using the GET method but for bulk data I am trying to json data using POST method. But after establishing the connection when I post the data I get an error. I am following examples on this page https://in.mathworks.com/help/thingspeak/bulkwritejsondata.html

The problem is the GSM module sends module specific error code and does not speficy the 40x or 50x error. So I am not able to pinpoint the error. I am attaching the commands sent by my device. Please guide.

[Christopher Stapels]

Can you try the same syntax in POSTMAN or curl to make sure your syntax is correct? I scanned it and it looks good to me, but the bulk update syntax can be really sensitive.

A quick search of the error you show seems to say it indicates a format or authorization error in the POST

[AirQo Data]

I can make a bulk post is similar structure but upto 5 entries. The server returns error when more than 5 entries are made. Interesting thing is all works well if i use a client class embedded library like tinyGSM

[Christopher Stapels]

What do you mean by "use a client class embedded library like tinyGSM". And does that mean you aren't limited by 5 entries if you use this other library?

Answer 1

[Christopher Stapels]

My guess on the five entries limit is the size of the data buffer used in your communication library. (either the arduino or the GSM.)