Strictly speaking that's no capture file, it is a screenshot of the sniffer output, which however shows that you do respond to the incoming PPPoE discovery frames but the client most likely doesn't react to these responses and starts sending the requests again.
So sniff into a file, download the file and open it with Wireshark. It will tell you whether what comes from the client is always PADI (which is 99% sure to be the case as the dst-mac is a broadcast one) and what you respond is PADO. I can theoretically imagine that the client doesn't say in PADI which service it wants to connect to although it has one configured, and then it dislikes the service name you offer in PADO because it doesn't match its configuration, but it is quite unlikely, so I vote for an L1 or L2 error in the direction from you to the client - from dirty fiber through broken laser in your SFP to misconfiguration on fiber provider's switches.
As the sniff shows that you try with just a single client, that one may also be broken itself.
Also your SFP may cry too loud for he sensitivity of the opposite one and the fiber attenuation.
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.