Hello, I'm on Ubuntu 12.04 X64 on 1GB Ram Droplet also I've Zpanel as CP.
Some emails are failling to be delivered.
I always get same messages for same sent email domains:
"Undelivered Mail Returned to Sender" and "Delayed Mail (still being retried)"
I made some pastebin for both messages. Here:
http://pastebin.com/sv8bdpQg and http://pastebin.com/5AeCFNRj
I don't know how to fix it.
This would be because your IP address does not have a PTR record assocated with it. This is odd, because the PTR should be the droplets name. I'd recommend that you adjust the PTR in the control panel (if possible), or contact support (if adjustment is not possible) requesting they create a PTR record for you.
According to Wikipedia PTR is a pointer record that point to a canonical name. Unlike a CNAME, DNS processing does NOT proceed, just the name is returned. The most common use is for implementing reverse DNS lookups, but other uses include such things as DNS-SD.
Well, ok. Now I'm aware of what is a PTR Record.
My droplet name's LalandeZ. I checked hostname command and it returned LalandeZ and I set it as z.lalande.com.br.
Shall it solve the problem for all my domains?
Not all domains, but if you have the MX records all point to that one domain, then when they do an MX lookup, and reverse the IP, it will match.
Good, then I'll wait for hostname change effectsand come back here to tell you if did work,
Hello, I just renamed my Droplet from LalandeZ to g.lalande.com.br and now email is fully working
Just to complement. I have many domains into this server. And none of this domains cant send emails to the same recipients.