system: cannot reserve inbound connection: resource limit exceeded"

[datong-new]

I run the same command as @realbiz21 mentioned in https://github.com/mudler/edgevpn/issues/29.

host1: sudo ./edgevpn --interface edgevpn0 --config config.yaml --log-level=DEBUG --address 10.1.1.1/30 --libp2p-log-level=INFO --transient-conn
host2: sudo ./edgevpn --interface edgevpn1 --config config.yaml --log-level=DEBUG --address 10.1.1.2/30 --libp2p-log-level=INFO --transient-conn

And the two peers behind NAT can not ping each other. But my debug info is as follow:

{"level":"DEBUG","time":"2023-01-02T15:58:20.789+0800","caller":"vpn/vpn.go:258","message":"could not handle frame: '10.1.1.1' not f
ound in the routing table\n"}
2023-01-02T15:58:21.104+0800    INFO    net/identify    identify/id.go:369        failed negotiate identify protocol with peer    {"
peer": "12D3KooWNAsC8qv6f55DScsvcm9n4HEePsuPh7NQL63xYp9KTdb7", "error": "Application error 0x0: conn-19203779: system: cannot reserv
e inbound connection: resource limit exceeded"}

The same error happens in other project like https://github.com/ipfs/kubo/issues/9432 . Thanks for any help.