Help is near! I've had this problem many times.. figured out the easiest way to resolve it is to close demigod, and close Impulse. Wait 15 seconds, then start up Impulse / Demigod. Try logging in. That has worked for me almost every time (if it doesn't.. I rinse / repeat, but wait like 30 seconds).
Weird I know.. but I've waited a long time just spamming my info to login with no success. I've tried closing and reopening demigod multiple times with no success. But.. closing Demigod AND Impulse + waiting = win. gl hf.