hi all 
still at beginer stage but have managed to set up a rasp pi with node red and MQTT and all working fine .
i have now set up a D1 mini to trigger a relay over MQTT from my pi and all working great , my problem is if i try and connect another D1 mini with different topic and try and connect the both then nether one with connect or opperate. i have tried to give one of the D1 minis a static ip address and that worked with changing the ip address but still cant connect both at the same time . im probably missing something obvious but dont realy know where to start looking . any pointers would be great .
this is my first post ,hope ive sent it right.
regards 
paul