Hallo,
I have a problem with the mail server, my mailboxes receive but do not send. I attach the latest log errors:
May 17 12:30:28 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:29 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:31 bustles postfix/smtpd[4128710]: connect from unknown[2.187.18.194]
May 17 12:30:31 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:32 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:34 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:35 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:36 bustles postfix/smtpd[4128710]: warning: unknown[2.187.18.194]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
May 17 12:30:37 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:37 bustles postfix/smtpd[4128710]: lost connection after AUTH from unknown[2.187.18.194]
May 17 12:30:37 bustles postfix/smtpd[4128710]: disconnect from unknown[2.187.18.194] ehlo=1 auth=0/1 commands=1/2
May 17 12:30:37 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:39 bustles postfix/smtpd[4128710]: connect from unknown[183.239.232.85]
May 17 12:30:40 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:40 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:42 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:43 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:45 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:46 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:48 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:49 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:51 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:52 bustles postfix/smtpd[4128710]: warning: unknown[183.239.232.85]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
May 17 12:30:52 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:54 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:55 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:30:56 bustles postfix/smtpd[4128710]: lost connection after AUTH from unknown[183.239.232.85]
May 17 12:30:56 bustles postfix/smtpd[4128710]: disconnect from unknown[183.239.232.85] ehlo=1 auth=0/1 commands=1/2
May 17 12:30:57 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:30:58 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:00 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:01 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:31:03 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:04 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:06 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:07 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:31:09 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:09 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:12 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:12 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:31:14 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:15 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:17 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:18 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:31:20 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:21 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:23 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:24 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]
May 17 12:31:25 bustles dovecot: imap-login: Login: user=info@bilanciosocialecoop.it, method=PLAIN, rip=::1, lip=::1, mpid=4128767, secured, session=<CsqFpDLfruQAAAAAAAAAAAAAAAAAAAAB>
May 17 12:31:25 bustles dovecot: imap(info@bilanciosocialecoop.it)<4128767><CsqFpDLfruQAAAAAAAAAAAAAAAAAAAAB>: Logged out in=91 out=1001 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0
May 17 12:31:26 bustles postfix/smtpd[4128332]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:27 bustles postfix/smtpd[4128710]: connect from unknown[5.34.207.56]
May 17 12:31:29 bustles postfix/smtpd[4128710]: disconnect from unknown[5.34.207.56] ehlo=1 quit=1 commands=2
May 17 12:31:30 bustles postfix/smtpd[4128332]: connect from unknown[5.34.207.56]