RunKeeper recently changed the way logins to their website is handled which broke the integration with RunGap. The problem has already been fixed in the most recent version 2.17.1 the App Store.
If you are still having issues after updating the app to version 2.17.1 then you might have an ASICS account with a different password than the one that you are using in RunGap and the RunKeeper app.
If this is the case then please log on to https://www.asics.com/us/en-us/login and change the password to match the one that you are using in the RunKeeper app.
It is important that these are the same because RunGap will need to log in using both methods.