Question: iPhone 5: for the last 3 days, unable to connect to Facebook, access imperial bux store. 

No issue with network connection and able to access Facebook thru the installed app. 

Exited app, powered down. Connected thru wifi and cellular connection. 

Anyone had success in fixing this?

Answer: 
Turn off the FaceBook app on your phone.

On iPhone 5, hold the Home button for about 3 seconds. You will see a line of your recently used apps.

Swipe up on the FaceBook app.

Android should have a similar method. This should allow you to connect in Tiny Death Star again. 

It is likely because both Tiny Death Star and FaceBool are born trying to connect to your FaceBook account.
DISNEY yanked the app off all system but windows systems