My setup:
Beelink Mini MXIII II (S905x)
LibreELEC 7.0.3.011 (kszaq) KODI 16.1
I was having the same problem with wireless connection that others have mentioned.
This morning I've noticed that with the Wired Networks button turned off (Settings/ LibreELEC / Network), the box is connecting to my wireless network automatically at start up without the need to toggle the Wireless Networks button.
I've tried this many times this morning and it has not failed. I also tried reactivating Wired Networks and the problem recurred straight away.
Interested to hear if this works for anyone else.