Thank you for sharing the screenshot. Please try the below steps and update the status.
1 The user name has been updated with the domain name on the configuration page, please update just the user name without domain name (remove @domain.com).
2 If the issue persists please update user name as 'admin' (for testing purpose) and try to configure.
3 If 'admin' works fine, please create a new user name for vRops and reconfigure it in Skyline.