Dear Forum,

I bought a TL-SG105E and it doesn't work. 
I couldn't get the switch to work and spent half an hour tinkering with it with a TP-Link support person via the hotline until he concluded that the unit was probably faulty and I should replace it. Now I got the replacement last week but the problem remains. The cable that goes to the computer has a permanent green light on the switch, the cable that goes to the rooter (Fritzbox) has green and yellow flashing synchronously every second. The computer has a self-assigned IP address and I cannot access the user interface of the switch. I have tried various cables. They all connect to the Internet when I connect them directly between the computer and the Fritzbox. Should I send both devices back, or is there still a way to salvage this? 
Many thanks for any help.

With kind regards,
Boris Goldammer