Mails are not going out from my nexus 5

[chinnu07]

I setup IMAP for incoming(port 993 SSL/TLS) and SMTP for outgoing(port 587 STARTTLS). Both are office365.com settings. Now I can receive emails but when I send it it's not going out. Just sitting outbox in my nexus 5.

I configured my personal office 365 email settings.

I am not seeing any error message also.

I verified with my earlier iphone and same kind of settings what I did for Nexus 5

What might be the issue ?