I researched and made several changes ==> in the end I checked my hosts file as well as resolv.conf for DNS, then I detected that port 25 was closed and that the cron generated an error such as :
cron: can not lock /var/run/crond.pid, otherpid may be 5199: Resource temporarily unavailable
By doing several searches and tested different solutions, I have come to install POSTFIX while removing sendmail and configured the main.cf ==> since port 25 has become active again, I modified the configuration.yml file Of redmine and since then I can send test emails from the server to the mailboxes of the company.
My concern is that I still can not send notification to every validation or modification made on REDMINE.
In the logs here is what I find:
Linux postfix / pickup : DC8737F4A7: uid = 0 from =
Linux postfix / cleanup : DC8737F4A7: message-id = 20170314154946.DC8737F4A7@redmine.domain.com
(Root @ linux), size = 372, nrcpt = 1 (active queue)
25x, delay = 0.24, delays = 0.01 / 0/0 / 0.22, delay = 0.24, delays = 0.01 / 0/0 / 0.22, Dsn = 2.6.0, status = sent (250 2.6.0 20170314154946.DC8737F4A7@redmine.domain.com [InternalId = 224276] Queued mail for delivery)
Linux postfix / qmgr : DC8737F4A7: removed
Help me on the direction I should take would be helpful.
Thank you for your help in advance and if need for additional information I will not hesitate to provide them to you