unable to find skrleton markers

[Cxli]

Hi I am using optitrack to create a baseline 41 skeleton. We customize a cloth to tight the markers to the body since the cloth will affect the data collection of our own sensors. But when we try to create the skeleton, we met the problem of unable to find skrleton markers. We already make sure that the calibration is correct and we also put the T pose. Is there any other problems which can cause this error?