Not sure about others but recent!y been getting please restart client a lot on both my devices despite having a very good internet signal. Happening every day for over a week.
Anyone else had this problem? TBH, it's always worked fine for me, not just saying that. :) Although I usually only have a couple of games on the go, so I only have to log in once every few days.
Just another thought on this: Just in case you haven't tried it, could you try using SF connected to wifi, and also try it using only your phone's data to see if either can connect?