Ok, I've changed the name of 2.4 & 5 wi-fi. On Android I see both of them and connect only in 5 ghz.
Then reboot in LE.But in LE I see only the 2.4 wi-fi.
Magnum
In Libreelec, go to the Libreelec configuration, then network? connections? disconnect, then reconnect to 5Ghz