How long are you waiting after clearing the cache for OH to start up?
Is OH crashing before it can start up? Run sudo systemctl status openhab2 to see if there are errors there.
After clearing the cache, (NOTE on a upgrade the cache is cleared automatically) give OH time to fully restart and come up (how ever long that usually takes on your machine). Then restart OH. Don’t clear the cache.
I have just discovered the same problem… no access to my UIs.
I upgraded from 2.4 to 2.5.4 last week but now, after a (possibly unrelated edit to addon.cfg file) a couple of days I get “Error 404” when trying to access https://openhabianpi:8080.
As suggested by @rlkoshak i completed command: sudo systemctl status openhab2
Below is copy/paste of results. Any ideas?
[11:55:23] openhabian@openHABianPi:/$ sudo systemctl status openhab2
● openhab2.service - openHAB 2 - empowering the smart home
Loaded: loaded (/usr/lib/systemd/system/openhab2.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2020-05-10 11:53:04 UTC; 8min ago
Docs: https://www.openhab.org/docs/
https://community.openhab.org
Main PID: 560 (java)
Tasks: 106 (limit: 4915)
CGroup: /system.slice/openhab2.service
└─560 /usr/bin/java -Dopenhab.home=/usr/share/openhab2 -Dopenhab.conf=/etc/openhab2 -Dopenhab.runtime=/usr/sh
May 10 11:53:04 openHABianPi systemd[1]: Started openHAB 2 - empowering the smart home.
lines 1-11/11 (END)
Thank you. My system has self cured also. I restarted everything (Pi and remotely connected laptop) and edited the addons.cfg file through by SSH terminal, as file editing through Visual Code and access through the UI was not working. That file issue might have been related to losing my access, but not sure.
Anyway - as we were!!!