Can't accommodate a PPPoE line on the MX450?

[zamisan]

I was thinking about a configuration in which the MX450 would house a PPPoE line.
However, when I connect it to the ONU with a LAN cable, it doesn't even link up.
I tried connecting with a straight cable, connecting with a cross cable, changing the cable, restarting the MX450, and restarting the ONU, but all efforts failed.
Is there a problem with the configuration of directly accommodating a PPPoE line on the MX450?

[ww]

What sfp are you using?

Did you set pppoe on the local status page?

[zamisan]

I'm using GLC-TE SFP.

PPPoE is already set on the local status page.

Link Negotiation is already set to Auto (1/10Gbps).

When I changed the connection method from ① to ②, the link was up and I was able to communicate with the outside world.

①MX450 --- ONU

②MX450 --- MS350 --- ONU

I don't know why, but is it really not possible to configure the MX to directly accommodate the ONU?

I think it's a pretty common configuration to accommodate the ONU in a router...