Originally Posted by DrunkenCount

I've had the same issue, but I noticed something in my playing pattern. As the new daily nation battles are available, I'd try them, get the error and lose the stamina. That would piss me off and I'd just do 1-1 to get the daily quest. Then when I try later, they work.

On Bergamont I just played 1-1 immediately and then started 5-1 and there were no errors.

Clearing cache and all of that jazz didn't help. Playing an earlier mission before starting new ones did.

This works for me as well. No idea why it works, but it does.