In public APP "shop/update" WEBHOOK removed from some stores by SHOPIFY

[ashishdots_18]

I am checking on my partner account app WEBHOOK metrics of my public app.  here  "shop/update" WEBHOOK removed from some stores by Shopify. I am finding a solution to why it's removed by Shopify but not getting any solution to track it's removal. We have returned 200 WEBHOOK responses all time.

Like :   echo JSON_ENCODE(array("status" => "200", "message" => "ok")); exit();

i know If your WEBHOOK didn't respond with a 200 series status code, then the delivery failed. If the delivery fails, then it's retried up to 19 times. A WEBHOOK is removed when 19 consecutive retried delivery attempts fail.

But we already returned 200 responses.

Please suggest a solution to how we can track it. Also what needs to update in my code. I am using PHP code.