How to enable STARTTLS encryption in Outlook 2016

Question

I am using OUTLOOK 2016 and STARTTLS is not one of the options for my Outgoing server connection encryption options. The only choices in the drop down list are NONE, SSL, TLS and AUTO. From what I can tell from other answers, it should be there as an option??

I am unable to upload a screenshot, so my settings under Account Settings > Change... > More Settings.... > Advanced are as follows:

Incoming server (IMAP) 993

Encryption type: SSL

Outgoing server (SMTP) : 25

Encryption type: Needs to be STARTTLS but I can only select NONE, SSL, TLS or Auto

My "Outgoing server" settings are:

• My 'Outgoing server (SMTP) requires authentication' is Ticked/Enabled
• 'Use same setting as my incoming mail server' is Selected

Please help as I cannot send outgoing emails :(

Answer 1

Dear Karl RussellTQ,

Thank you for posting in the Microsoft community.

I understand that you can't select the STARTTLS encryption method in the manual configuration of Outlook 2016. To pinpoint your issue more accurately, could you please share more detailed information with me:

1. What is the suffix domain name of the email you want to configure? For example, @outlook.com.
2. What is the specific version number of your Outlook?

Since I can see this encryption option on all my test devices at present, I can't replicate your problem. I've sent you a private message.

Private Messages - Microsoft Community

Please share screenshots with me via the private message as much as possible. This will help me analyze your problem.

(If the screenshots are not uploaded correctly, please refresh the page or change the browser and try to upload again.)

Please believe that I'm really eager to solve your problem, so I hope to get your cooperation.

Thank you for sharing more detailed information with me. I'll keep an eye on this thread and give a further reply as soon as possible after receiving your reply. I'm looking forward to your reply and wish you all the best.

Best Regards,

Ulrica.W - MSFT | Microsoft Community Support Specialist

Answer 2

PM sent.