Hi, I am in the same situation. Kibana worked for me, then after some time while playing with indexes it started to behave strangely, finally after a reboot it refuses connection to port 5601
I tried to uninstall, deleted all /opt/kibana files, reinstalled latest version, nothing is working
I even cannot access any log, I created a log file for kibana and set it into kibana.yml but it is always zero sized.
The service starts after an initial failure but connection to the port is denied.