This happens to me, if your damage and defense multiple is to high, try to lower it.
try it in
Damage: 3-5(5 is my MAX Damage, sometimes the (Damage: 5) it gets an Error so I have to lower it to Damage: 2-3)
and for Defense: range it to 5-10(10 is MAX in my Campaign I haven't tried the damage...
IDK IF THIS WILL WORK
Go to
SUB MENU > Account > (at the bottom find the) Link/Linked Email
(The image below I've already linked it. because when you check it, it's still not linked)
then try to Linked your Gmail/email account that you use in the "Sign in with Google Account" Login Method.
(I...