Hi the documentation related to Proxy seem incomplet:

https://lemonldap-ng.org/documentation/2.0/authproxy

First, in the manager Proxy is not appear as a choice for auth and user as described in docs.

And maybe more usable to provide a sample of overloading in .ini with the right parameters name

In 1.9 I have set for soap:

authentication = Proxy
userDB = Proxy
soapAuthService = https://auth.interne.urgences-sante.qc.ca/