With Microsoft, users can connect to external SMTP servers. This can be useful to send emails to a domain that is different than the standard DNS. By using this service, users can send emails even if the public domain is outdated and/or has incorrect domain information. Many professionals use it on a daily basis to send out emails to different sites. SMTP can be easily set up from within Office365. You can then control the delivery of specific emails to specific domains. You won’t even have to worry about the DNS records saved on the server.
SMTP for Office365 should be in perfect condition at all times. This is necessary when sending out important emails, which may include clients important for business. But what if smtp.office365.com is not working for you? For the users who are unable to use SMTP for Office 365, read the list below. The following list has some solutions that you can try to fix Office365
Fixes for smtp.office365.com not working:
1) Cross-check the requirements for client submission:
Make sure that you are following all the protocols set for client submission. There are four requirements for SMTP client submission – Authentication, Mailbox, TLS, and Port. Authentication refers to the configuration of a user name and password. These credentials will be implemented for your account.
Users also need to have a licensed mailbox on Office365. TLS or Transport Layer Security should be supported on your device. The minimum requirement is TLS version 1.0. Port 587 or 25 should be allowed on your network. It is also possible that your firewall is blocking one of these ports.
After ensuring that you are following all the protocols, try connecting to SMTP again. Open the command prompt by typing CMD in the Windows search box. In the command prompt window type, ‘telnet’. This will open the tool required to connect to the SMTP server. Type the following line in the dialog box –
open smtp.office365.com 587(25)
If the problem was fixed, you should receive a message indicating a successful SMTP connection to Office 365.
2) Temporarily disable antivirus:
As mentioned earlier, a firewall or antivirus can block the necessary ports that are required to form an SMTP connection. To work around this problem, disable your antivirus for the time being. Try using smtp.office365.com again.
3) Printer settings:
Make sure that the settings for your printer are all accurate. Enable TLS and set the preferred port to 587 or 25. Enter the correct credentials when asked. Also, keep in mind that your printer will most definitely ask for your password and username. If it does not, it might be trying to send an email without logging into your Office365 account.
For more details, you can check out this extensive guide by Microsoft on how to set up an SMTP server using Office365.