if you're trying this over tcp you probably need to add an interface or just a remote point to link to it
try adding this to meshchat's config file
[[sideband]]
type = TCPServerInterface
enabled = yes
remote = sideband.connect.reticulum.network
listen_port = 7822
or read this https://reticulum.network/manual/interfaces.html
Idk if you're connecting over tcp or lora but you're better reading the docs