Xfi Security blocking friend from connecting to Minecraft server

I've been hosting a Minecraft server for my friends for a while now. Recently whenever my friend tries to connect they receive a message that they cannot connect to the server because they have been "timed out" After a bit of digging I found that Xfi Advanced Security had blocked their IP from connecting as it is a "known malicious IP." The thing is, they also have Xfinity Internet, and prior to this, they were able to play on the server without an issue.   How do I unblock their IP without disabling advanced security?