Error to send alert mail

[J1 Simón]

I have opened a bug about this error: 
https://savannah.nongnu.org/bugs/?37355

Gentoo 64 bits
monit 5.5

_The problem_:

Recently I have updated to version 5.5 and now it doesn't work the 
alerts by mail. With previous version worked. The relevant part of monitrc:

set mailserver smtp.gmail.com port 587
username "address@hidden" password "mypassword"
using tlsv1
...
set mail-format {
from: address@hidden <mailto:address@hidden>
subject: monit alert -- $EVENT $SERVICE
message: $EVENT Service $SERVICE
Date: $DATE
Action: $ACTION
Description: $DESCRIPTION
}
...
check device rootfs with path /
if space usage > 93% then alert
alert address@hidden <mailto:address@hidden> with the mail-format {
subject: monit alert -- Disco duro casi lleno!!!
message: El espacio ocupado del disco supera el 93%
Date: $DATE
}
...

Today the warning occurred but it did not send any mail.
I have consulted the sent and spam folder of Gmail account but there 
isn't any alert message.

Log file:
....
[CEST Sep 15 11:03:00] error : 'rootfs' space usage 93.5% matches 
resource limit [space usage>93.0%]
[CEST Sep 15 11:03:30] error : Sendmail: error receiving data from the 
mailserver 'smtp.gmail.com' -- Resource temporarily unavailable
[CEST Sep 15 11:03:30] error : Aborting event
....

I have configured my ssmtp server to use Gmail stmp server following 
this guide: http://www.gentoo-wiki.info/HOWTO_Gmail_and_sSMTP and I can 
send mail using "mail" command. Then, I think the problem is only in monit.
Regards.