This is probably due to the fact that you are trying to log into an XIQ Connect account which is not supported on this App. Here's an article on same: https://extremeportal.force.com/ExtrArticleDetail?an=000109111
Is this the case?
Thanks for posting this issue for us. I've been speaking with our XIQ techs about this and the first thing everyone is asking is what firmware is your iPhone using and have you updated it recently? If you can let me know I'd appreciate it, and I'll pass on any other troubleshooting steps/questions I hear of.