Wifi icon is blurred and cannot connect

[lovevn]

Hi all,
I have had a problem for some weeks.
Earlier, I connect to my wifi normally and, every time I turn on my laptop and log in Ubuntu, it connects to wifi automatically.
But now, I cannot connect to my wifi, because the wifi icon is blurred I must reset tp-link and then I can connect, but it's very inconvenient.
You can see the picture below:
As you see, my wifi is Duc Mai, but it's blurred! What happened?

[praseodym]

Open the network-manager as sudo-user

gksudo nm-connection-editor

and tick "connect automatically"

[lovevn]

Open the network-manager as sudo-user

gksudo nm-connection-editor

and tick "connect automatically"

Thank you for reply. But my main problem is I can't click on Duc Mai wi-fi icon - it's blurred even though I ticked "connect automatically" (as you see the picture: others is enable to click to connect, but Duc Mai isn't).
Today, I'm surrprised. Duc Mai wifi icon comes to normal.