Issue with printer(ZD500R) alerts on iOS

I am using ZD500R printer with my iOS app. I am able to get alerts from printer using TCP/IP connection. But I am facing an intermittent issue where alerts are not coming to app, but printer is still connected to app and I can execute print operations. To solve this issue, I have to restart printer and then it works fine.

Can anyone please guide me or suggest solution to fix this problem.

Please Note: I have used packet sniffing tool as well to check if printer is sending any alert or not. Printer was not sending any alert to specified port and IP address.