Aleatory problem sending emails for reports/scripts

I have about 6 or 8 Mikrotiks (751, 950, 951), all in version 6.23
I am having troubles for sending emails, all are using the same SMTP server, same account for delivering to the same address.

The logs for emails are not very extensive, and I am connecting to the SMTP server but in 99% of case in the half of the routers I can´t send the emails.

Here, a log…

11:43:44 system,info netwatch host modified by admin
11:44:06 e-mail,debug send RSET
11:44:06 e-mail,debug recv: 220-ks4003xxxxxxx.net ESMTP Exim 4.86 #2 Wed, 04 Nov 2015 05:44:06 -0500
11:44:06 e-mail,debug recv: 220-We do not authorize the use of this system to transport unsolicited,
11:44:06 e-mail,debug recv: 220 and/or bulk e-mail.
11:44:06 e-mail,debug send QUIT
11:44:08 e-mail,debug recv: 250 Reset OK
11:44:08 system,e-mail,error Error sending e-mail <AP 5.8 Campanillas up>: SMTP server not ready

If you see, the mikrotik is connecting and exchanging info, but its sent a QUIT command…

The emails params are the same (copy/paste) from one to another, my own Mikrotik is working well, but other mine in other isolate place with the same king of connection is NOT working.

Here the configuration..

set address=142.4.209.xxx from=routers@xxxxxxxxx.com last-status=failed password=xxxxxx user=
routers@xxxxxxx.com


The netwatch command/monitor that is delivering the email

/tool netwatch
add down-script=“/tool e-mail send to="monitor@xxxxx.com" subject="AP 5.8 Campanillas down" body="AP Ubiquit
i 5.8 in Campanillas with IP 192.168.75.2 is down since $[/system clock get time]"” host=192.168.75.2 interval=
10s timeout=508ms up-script=“/tool e-mail send to="monitor@xxxxxxxx.com" subject="AP 5.8 Campanillas up" bod
y="AP Ubiquiti 5.8 in Campanillas with IP 192.168.75.2 is up since $[/system clock get time]"\r
\n”

Both email address exists in my own server and send and receive emails…

also, I have a init script for notifying when the router become online, and its failing too…

I dont understand why is working in some routers and in other not…

Thank you