Using Ubuntu 16.04 LTS on a Toshiba Satellite A665 box.
Whenever the screen dims, the computer displays the following message when it wakes up on a mouse movement:
Wi-Fi Network Authentication Required
Passwords or encription keys are required to access the Wi-Fi netowrk 'RiverMain-RES'
Text box labeled password with the correct password already entered.
Two buttons labeled "Cancel" and "Connect"
Clicking on "Connect" closes the message box, but does not reconnect the Wi-Fi.
Wi-Fi can be reestablished by clicking on the network icon in the upper left corner of the screen and selecting 'RiverMain-RES' from the drop down. It can also be established by re-booting.
This issue can be resolved by setting the "Dim screen to save power" option in Locks and Brightness to "Never", but that leaves the screen continuously illuminated Not the optimum.
This issue is important because I am using teamviewer on this box to communicate and monitor my 92 year old, visually impaired, Parkinson's afflicted father from my home in Mexico. If the connection goes down I can't remotely control his computer and it is very difficult for him to reestablish the connection. I have been instruction him to power down then back up as a work around, but i have no doubt that you can see that is problematic. I guess we can live with having the screen constantly illuminated, but I would welcome any ideas.