Question Let´s Encrypt and reverse proxy

[KristallCarlo]

We want to install a second plesk server. We also want to use 1 public ip-address. Therefore we have to install a reverse proxy (haproxy) which will redirect the incoming requests.
The domains in plesk are using Let's Encrypt and this can be an issue. When haproxy is active the let's encrypt server can't communicate anymore with the plesk server. Is there a workaround for this ?

Or is there a better methode to use 2 plesk servers with one 1 public address and Let´s Encrypt.