On 15 May 2018, at 12.06, Timo Sirainen <tss@iki.fi> wrote:

If you look at .176's error log, do you see an error about "director_consistent_hashing settings differ between directors"? Have you set director_consistent_hashing=yes in the old directors? That is needed now, because the old non-consistent-hashing method is obsoleted. Unfortunately there's no easy way to upgrade directors to use the consistent hashing method without stopping the entire ring. The hard way would be to build a secondary director ring and start moving users to that ring in proxies.

Added https://wiki2.dovecot.org/PasswordDatabase/ExtraFields/Proxy#moving to explain further the hard way.