Proxy testing in container( chown failed /var/dovecot/login)

I am testing a bit with the proxy, and trying to run dovecot as a normal user. (with cap bind_service). I was wondering what the minimum configuration is for running like a proxy.

I am now getting issues like unable to chown on /var/dovecot/login, but I do not need this in such a setup do I?

passdb { driver = static args = proxy=y host=192.168.11.10 nopassword=y }