SOLVED: Can't connect to server

[TheDreadPirate]

......Is your Fritzbox putting each WIFI band on separate VLANs? That is not normal home router behavior. On most routers, at least here in the US, you have to explicitly separate WIFI clients. Out of the box, all WIFI clients can talk to each other and are on the same VLAN regardless of what WIFI band they are using.