M66 Gsm module sending 0 every 9 seconds

I am using M66 M66FAR01A04 GSM module. The problem I am facing is that it is sending 0 every 9 seconds as response wether I am executing any command or not. It’s just sending 0 on uart. Is this normal behaviour or not? How can I stop this?

Dear Sir,
You can use the following AT command to check the keep alive parameters setting, for your issue, i think you can try to close the heartbeating function with AT+QIKALIVE=0. If still can not solve your issue, it is better to catch the module AT log and debug log to confirm the reason, and you can send email to support@quectel.com to get our local FAE support. Thanks!

AT+QIKALIVE? //check the default value
+QIKALIVE: 0, 60, 10

AT+QIKALIVE=0 // close the heartbeating function