Gateway never seen- chirpstack server

I am facing a problem with chirpstack server.
my gateway is connecting to older version of chirpstack server (loraserver). I had older version in server and I
deployed chirpstack server which is available now in onther server. I configured everything fine with no errors. But my gateway is not connecting to the server. Help me to get this problem to fix.


Make sure udp port 1700 is open

did you reconfigure gateway to connect to new server and right port? check gateway and server date/time also.