If you use multiple devices to access your IDF profile, you might encounter the following error:
503: Service Temporarily Unavailable
Too many IP addresses accessing one secure area!
Please contact Support if you need assistance.
That means you have used more than 10 different devices in the last 30 days.
The solution is easy: wait one hour and you can log in again.
Why this 'rule'? It's a security precaution. That's it, but no worries, 99% of you will never get to see this message.