sendemail trough exchange server smtp ssl / starttls problem

[rezatbaher]

when i try to send 50 emails using sendemail i get this log in a random number .
command im using is this :
sendemail -l email.log
-f "[email protected]"
-u "Automatic email"
-t "[email protected]"
-s "smtp.mailserver.com:587"
-o tls=yes
-xu "username"
-xp "password"
-o message-file="tempemailbody.txt"

with gmail and postfix there is no such problem .
this is not because of network , i did netcat to exchange server and even telnet to verify before sending each email but happened again .
ERROR => TLS setup failed: SSL connect attempt failed error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed

sending email using ssmtp has no problem with exchange server

[fredzannarbor]

There are several versions of TLS and earlier ones have security flaws which means that they are deprecated. I would check to see what TLS is required / used in each of these environments.

…

On Mon, Aug 26, 2019 at 2:54 AM rezatbaher ***@***.***> wrote: when i try to send 50 emails using sendemail i get this log in a random number . command im using is this : sendemail -l email.log -f ***@***.***" -u "Automatic email" -t ***@***.***" -s "smtp.mailserver.com:587" -o tls=yes -xu "username" -xp "password" -o message-file="tempemailbody.txt" with gmail and postfix there is no such problem . this is not because of network , i did netcat to exchange server and even telnet to verify before sending each email but happened again . ERROR => TLS setup failed: SSL connect attempt failed error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed sending email using ssmtp has no problem with exchange server — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#19?email_source=notifications&email_token=AAI4TSYGB65HSH6O7JLV53DQGN4ZJA5CNFSM4IPMNQKKYY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4HHJVMWQ>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAI4TS4JYLUCYHNQZAMY7NDQGN4ZJANCNFSM4IPMNQKA> .

[pranavkinicok]

I cant even send single mail
Command that I used is :-
senemail -f **@gmail.com -t **@gmail.com -m "test" -xu "username" -xp "password"

The output that I get is:-
Connection refused =>