Hello ,
I have installed SMTP role on Windows server 2012 r2 (local virtual smtp server)and host on IIS to send mail Smart host:smtp.office365.com . It was working properly last six months..suddenly I found it stopped to send mails .
for troubleshooting I can able to get mails yahoo, gmail account from local smtp server using telnet command from sender as company domain user account of office365  but not able to send mail  recipient to company domain user account of office365 . getting timeout in log file....I could not able to fixed why its happening and to resolved the issue...

followed link for configuration :https://technet.microsoft.com/en-us/library/dn592151(v=exchg.150).aspx

Any help or troubleshooting steps..welcomed.
Thanks
RICHA KM

• Edited by Richa km 19 hours 41 minutes ago