Gamingmate92 0️⃣ So then, let's start over, disconnect everything, reset everything, ONT, FRITZBOX, let's start again trying to understand the basics of your setup... 🔄
1️⃣ After doing these steps, restart everything by disconnecting the devices from the power supply for at least 2 minutes, be careful that before disconnecting everything you need to see if the boot is finished on all devices and everything has realigned correctly with the delivered configuration
2️⃣ Out of curiosity, do you still have the original RJ45 cable that came with the ONT? (Which should be ZTE) It should be a yellow cable, well use that to connect the ONT to the FRITZBOX later 🟡
3️⃣ Now before putting it back into service and trying with the FRITZBOX in the chain, let's try to connect directly with a PC to the ZTE ONT by setting a static IP address on the PC network card
4️⃣ After doing these steps (clearly the PC must be freshly rebooted too) give us some photos of your setup related to the steps above and then we continue after your reply to this...