Are all of your Amcrest IP2M-841B cameras on WiFi, or does this problem happen even when your cameras are connected to a wired network?
We sometimes see this happen when the WiFi signal is not great, causing the camera to fail to respond quickly enough when we query to see if it has WiFi.
This assumes you haven't done anything unusual, like create a separate user account on the camera. (If you did that, then of course you'll have to make sure that user has permission to use PTZ.)