My OpenHABianPi has ethernet WIFI connection and is placed in my summerhouse 150 Mi away.
I’ve been running lights/door sensors/temp sensors remotely since last spring.
The device has two times during this period gone offline for about two weeks, before it decides to go online again. I haven’t done anything to correct the problem; it has corrected itself.
The WIFI connection works fine (my Arlo Cams work perfectly).
You may have to expand a bit on what that means. Are you making a local connection from the house, say from a browser? What URL - by name or by IP etc.? Or are we talking a myOpenhab thing?
