As a client, only connects to open wifi

using 18.06 on my hg553 as a client for the wireless network created by my android phone. if the network is open, without any password, it seems to connect rather smoothly and stays connected.
Using passwords seems to be what creates problems: funny thing is some days ago it worked but it doesn't anymore. Oddly, it didn't work at first when I used a complex password (like pass4444) but began to work when I only used characters (like "password")