Zigbee is having significant problems for many people right now, regardless of brand of device or dth/edge driver being used. This includes adding new devices.
This problem started with the hub update two versions ago, was supposed to be fixed in the most recent update, but several people have reported the problem persists. So it’s just hard to troubleshoot any zigbee devices right now. 
See discussion thread:
Aeotec Smart Home Hub/2018/2015 Model Hub Firmware Hotfix Notes - 0.45.11