No, you’re not doing anything wrong. I was just stating that you might try a test with an Ethernet port to verify the issue is with the SFP port and not something else. Use ether6. You won’t get 3Gb speeds, but you’ll get something more than you have and can verify.
If I set sfp as Wan in interface list and ether 1 as wan in adresses, its all up and running, but I dont know if we are getting the 3gb since I also connected ether1 to the fiberbox.
So sfp connected between fiberbox and rb4011 and network cable between fiberbox and rb4011.
What gives you confidence that the SFP is compatible with the fiberbox? Previously you have an RJ45 connection. That SFP module is single mode 1310nm. Is your ISP good with that? Look at the status of the SFP module and see what it is reporting. The fiberbox, is it something like a multiplex?