i stopped the zimbra suite , changed the permissions on the file and inserted the url
cat /opt/zimbra/cyrus-sasl-2.1.21.ZIMBRA/etc/saslauthd.conf
zimbra_url:
http://zimbra.mydomain.net/service/soap/
zimbra_cert_file: /opt/zimbra/conf/smtpd.crt
zimbra_cert_check: off
then saved and started the zimbra
bin/zmcontrol start
Host zimbra.mydomain.net
Starting ldap...Done.
Starting logger...Done.
Starting antispam...Done.
Starting antivirus...Done.
Starting snmp...Done.
Starting spell...Done.
Starting mta...FAILED
saslauthd[11005] :set_auth_mech : failed to initialize mechanism zimbra
zmsaslauthdctl failed to start
then i checked the saslauthd file and it was missing the url again :
[root@zimbra ~]# cat /opt/zimbra/cyrus-sasl-2.1.21.ZIMBRA/etc/saslauthd.conf
zimbra_url:
zimbra_cert_file: /opt/zimbra/conf/smtpd.crt
zimbra_cert_check: off
[root@zimbra ~]#