Why can't some sites open via EoIP?

Question

Computer networks

Given: EOIP connection. Both nodes have white IPs. On the second node, the Internet connection is via ppoe, mtu on ppoe 1492 . On the first node, the ipoe connection is available - and on the first node, Yandex is available without problems. On the second node, all sites open except for Yandex and a couple more sites.

Answer 1

calculate the MTU of the EOIP pipe with pings
and set tcp mss adjust to the mtu value minus 40 on the router on the Internet . convert to normal L3