I have recently set up zigbee2mqtt on Home Assistant in place of my Aqara Gateway. Most of my devices pair with no issues other than two:
Honeywell Smoke Detector. Despite pressing 3 times according to the instructions, it seems that it doesnt go into paring mode at all (this was also the case with the Gateway until magically one day it just worked)
Aqara Temp sensor - lights up quickly 3 times after pressing for 5 secs but then does not show up in HA.
I suggest you check the zigbee2mqtt logs to see what happens during the pairing. I couldn’t get some of my Aqara stuff to pair until I upgraded zigbee2mqtt to the latest.
Another thing that might help : stop zigbee2mqtt, disconnect your CC2531/CC2530, reconnect your CC2531/CC2530, start zigbee2mqtt and try pairing again.