FRITZ!Box 7581 Service - Knowledge Base
Using storage (NAS) connected to FRITZ!Box with Apple Time Machine
You cannot use a USB storage device connected to the FRITZ!Box with Time Machine.
Only external hard drives connected directly to the computer via Thunderbolt, FireWire or over USB, the integrated hard drive of an Apple Time Capsule and drives of other computers in the FRITZ!Box home network with macOS are suitable for use with Time Machine.
Note:You can use a network cable or wireless LAN (WiFi) to connect an Apple Time Capsule to the FRITZ!Box and then use it on every computer in the home network. Refer directly to Apple for information on Time Machine and Time Capsule, for example consult the manual.