Appium cannot find android virtual device launched by genymotion

I’m using 2 hosts to serve a selenium hub as its nodes. I have installed appium+genymotion on these hosts and all of them are with the same configuration except for their respective ip addresses. Before startup appium, I use genymotion to launch 1 android virtual device on each host, with the same device definition, and all the devices are launched successfully. Then I startup appium on all the hosts successfully. (Let’s call the 2 appiums Appium-A and Appium-B)
Now, here the weird thing goes: when a testing request comes from selenium hub and is dispatched to Appium-A, Appium-A fails to create a webdriver session and tells, it cannot find any avail virtual device to connect. However, when the request is dispatched to Appium-B, it works fine to create a webdriver session and complete the test case.

Did anybody ever meet such issue before? And how did you get it solved, please?

facing a similar problem ,where in the Appium A is my android device and Appium B is my genymotion virtual device.
Unable to launch on the virtual device.