emails, Error 550 5.1.1.

Thank you all
I hope you understand what is written below.

And thanks for helping me I've been having problems with the server for 35 days.

With These Problems But Still, I find the best CWP Panel Host free ..
I have CWPpro ;-) I advise all this panel ..



I installed CWP on CentOs7 .. I put email on the System sistema@domiani.com. I changed Hostname to Server, When Receiving emails, Error 550 5.1.1. Create new email and it works well .. I went to see the error log, Name hostname is the old one, I ask it has nothing to do with the error?


log erro email

Feb 14 10:45:01 vmi-old postfix/qmgr[1004008]: CB000000: from=<>, size=20000, nrcpt=1 (queue active)
Feb 14 10:45:01 vmi-old postfix/qmgr[10000]: BAE00000: removed
Feb 14 10:45:01 vmi-old postfix/cleanup[10000]: D1000000: message-id=<2000000000.C0000000000@serviot.jonyhost.site>
Feb 14 10:45:01 vmi-old postfix/local[10000]: CB0000000: to=<root@newserver.domain.com>, relay=local, delay=0.03, delays=0.02/0/0/0.01, dsn=2.0.0, status=sent (forwarded as D14FE10A09E0)
Feb 14 10:45:01 vmi-old postfix/qmgr[10000]: CB0000000: removed
Feb 14 10:45:01 vmi-old postfix/qmgr[10000]: D10000000: from=<>, size=2897, nrcpt=1 (queue active)
Feb 14 10:45:01 vmi-old postfix/pipe[10000]: D10000000: to=<sistema@domiani.com>, orig_to=<root@newhostname.domain.com>, relay=dovecot, delay=0.03, delays=0.01/0/0/0.02, dsn=5.1.1, status=bounced (user unknown)
Feb 14 10:45:01 vmi-old postfix/qmgr[14198]: D100000000: removed
Feb 14 10:45:52 vmi-old postfix/smtpd[10000]: connect from localhost[127.0.0.1]
Feb 14 10:45:52 vmi-old postfix/smtpd[10000]: disconnect from localhost[127.0.0.1]
Feb 14 10:46:50 vmi-old clamd[14031]: SelfCheck: Database status OK.
Feb 14 10:47:07 vmi-old postfix/anvil[10000]: statistics: max connection rate 1/60s for (smtp:000.000.000.000) at Feb 14 10:41:39
Feb 14 10:47:07 vmi-old postfix/anvil[15641]: statistics: max connection count 1 for (smtp:000.000.000.000) at Feb 14 10:41:39
Feb 14 10:47:07 vmi-old postfix/anvil[15641]: statistics: max cache size 2 at Feb 14 10:41:57



With These Problems But Still, I find the best CWP Panel Host free ..
I have CWPpro ;-) I advise all this panel ..
CWP There is no bug. I have little knowledge of Linux and CentOs ... This is the biggest bug ;-)

Thank you all

Your question is almost indecipherable. 

LMGTFY:
https://bobcares.com/blog/how-to-fix-550-511-recipient-address-rejected-error/

My guess:
/etc/postfix/main.cf

myhostname = (Your old hostname)

BUt just a guess.

If it's true, run the command
grep oldhostname *

to find all of the instances you need to change.
alternatively
sed -i "s@oldhostname@newhostname@g" /etc/postfix/*

thank you very much to the forum staff who help me .. I have to learn a lot.
I speak a little English, But writing has to be with Uncle google, sorry for mistake

my server VPS

Monitoring via Monit


Program - postfix-queue   Status failed

Error, don't care ..
Send and Receive email Ok

I ask;
My guess:

Why doesn't he call (start)?

OVH domain ..
Server Contabo .. Server-VPS Hostname  nameserv.mydomain.com

I think it is poorly configured at OVH.
It is like this..

Menu OVH configuration-> [Zona DNS]    [Server DNS]   [Forwarding]   [DynHost]     [ GLUE]     [Recent operations]

(configuration at OVH)-> Zona DNS

mydomain.com The IP
* .mydomain.com The IP
www.mydomain.com The IP

This configuration, Do not project the configuration emails?
I'm using free DNS

          ------------------//----------------------
dig my vps, resolved

[root@nameserv ~]# dig mydomínio.com MX

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-9.P2.el7 <<>> mydomínio.com MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32055
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;mydomínio.com.                 IN      MX

;; AUTHORITY SECTION:
mydomínio.com.          299     IN      SOA     dns103.ovh.net. tech.ovh.net. 2020021300 86400 3600 3600000 300

;; Query time: 17 msec
;; SERVER: 8.8.8.8#53(8.8.8.
;; WHEN: Sun Feb 16 10:48:22 CET 2020
;; MSG SIZE  rcvd: 97

[root@nameserv ~]#
 
                      ------------------------------//--------------------------------

my serverDNS freeDNS ns1.centos-webpanel.com IP  ns2.centos-webpanel.com IP

It's not correct. Is something wrong?