Unable to Access a required internet resource.

Game will not load using wifi. Worked fine at the start of today on the same wifi network, halfway through the day the game started an infinite loading wheel, and hit me with a connection error message and nothing I have tried seems to fix it.

Using iPhone. Have never had a connection issue last more than 2 minutes on this game. Haven't changed anything to do with my wi-fi or network. Downloaded today's update using data. Can't clear app cache on iPhone so I uninstalled and redownloaded. 

All other apps -youtube etc load fine on wifi, I even tried other similar live service games, DB Legends and Raid work fine.

Can't be forced to play the game on data- hope this has a fix.