On Sat, Jan 30, 2021 at 09:39:01PM -0700, Bob Proulx wrote: > My best guess is that your chroot does not have a working resolv.conf file.
Certainly a good place to start. The only odd detail is that the errors are 5.3.0 errors, so the lookup returned a definitive "no such host", rather than just failing to get an answer. Another possibility therefore, is that the OP (who failed to post "postconf -nf" and "postconf -Mf" details) has disabled DNS lookups entirely, either in main.cf or in master.cf. The correct (default) values of the relevant parameters are: # "yes" is almost never the right setting. # disable_dns_lookups = no # For MTAs setting mail directly to the Internet, # "dns" is the only correct value # smtp_host_lookup = dns The OP should probably post "postconf -nf" and "postconf -Mf" output as explained in: http://www.postfix.org/DEBUG_README.html#mail -- Viktor.