I use archlinux and network-manager, and every now and then, I failed to connect to a certain wifi, while the other wifi worked pretty well. I didn’t figure out the reason, but I found a solution.
First check which wifi connections do you have.
sudo ls /etc/NetworkManager/system-connections
Suppose we have a problem connecting to
OpenWrt15, what we need to do is just run the following command to move
OpenWrt15 to another location(Warning: make sure you know the wifi password of
OpenWrt15 before moving the file, because you will need to re-input the password again later on. Usually you can find the password in the
sudo mv /etc/NetworkManager/system-connections/OpenWrt15 /tmp
Then restart NetworkManager.
sudo systemctl restart NetworkManager.service
And try connecting to that wifi again. You will need to re-input the password. If you don’t know the password, you can probably find it in the original