That is interesting because with a default Windows 10 setup, Defender does not block the application.
Good to know that it does sometimes cause an issue though. 
Unfortunately, the eM Client stopped working again, without any changes.
Both of the two computer stopped working (receiving is ok), I don’t know what’s the reason, maybe caused by the remote email server?
Well, Tuesday was patch day for Microsoft. Maybe the update reversed the change you made?
it doesn’t work, and one more problem is, in Sent folder, there is no emails there. While in Outlook, there are lots of sent emails in “Sent Items”
I had this huge e-mail typed up because I was having the same issue, just with a DreamHost e-mail account and then, somehow because of this thread, I noticed that there is actually a manual way to add e-mail addresses. The manual method allowed me to get the SMTP option. Here’s what I did:
- Menu > Tools > Accounts
- For the e-mail address that was missing SMTP (my non-gmail accounts)
- Click on that account
- Copy the name in the account name (I just don’t want to keep re-typing this)
- Click on Trash icon for that account
- Click Yes to Delete account
- Click + to add a New Account
- (Instead of Automatic Setup) Click the down arrow next to Mail
- Click Other
- Click Next
- Paste the address name (from step 4. If you skipped this, then you get to manually type it in. Yay!!!)
- Now google your “incoming mail config {mail server name}” which in my case, would be Dreamhost
- Enter in your incoming mail config details. They are usually imap.{mail server name}.com
- If needed, type in your user name (the program might have it save from a previous entry)
- Type in your password for that account
- Click Next
- Now google (in a separate tab or browser window) “outgoing mail config {mail server name}” which, again, in my case would be dreamhost for the mail server name
- Change the Outgoing server details to whatever your mailing host says. It is usually smtp.{mail server name}.com
- (I didn’t check the “Outgoing server doesn’t require authentication” because I was hoping it does. It worked fine for me)
- Click Next
- If testing gives 2 green checkmarks, you are good. If something is wrong, go back and change it. Or respond here.
- Click Next
- Under “Your name”, give a name that has meaning to you. It won’t affect anything.
- Click Next
- Click Finish
And that is 25 steps to having a better experience with eM Client. I hope this helps you. I’ve been looking for this solution for too long. This thread inspired my solution, so I am happy to pay it forward from here.
I wonder if I can add the tag Enter SMTP manually here as a name for this solution so the search engine can find it.
Thanks for that.
You can also find useful setup instructions in the Help File ( F1 ) which explains (with pictures included) how to setup your account both automatically and manually. Check out Getting Started > Create New Account.
Your email provider should provide the details you need in one place. Sometimes, especially with hosted domains, the host name could well be different from address domain, so always best to check with them if there is some problem.
In your step 21, if the settings don’t work, check that you have correct security policy for the port you are using. The best options are:
SMTP Port 587 = Force usage of SSL/TLS
IMAP Port 993 = Use SSL/TLS on special port (legacy)
POP3 Port 995 = Use SSL/TLS on special port (legacy)
And if you have used these and it still doesn’t work, try disabling your anti-virus application.
Thanks, Gary!
For DreamHost, the SMTP port that finally worked was one that isn’t one of those that you listed. It’s the one DreamHost doesn’t recommend since it is usually blocked by ISPs.
I’m trying not to judge. = )
Maybe now that I have the manual option available to me in the Accounts area, I’ll try one of the other, more secure ports.
One particular email address would not send outgoing email on any device. The email provider suggested resetting all passwords. They still didn’t send. Trying to determine options to resolve the issue and because of periodic issues with eM, I decided to delete the email account on eM. When I set it up again (deleted and attempted set up 4 more times; attempted both automated and manual) it still doesn’t work. I can’t get SMTP to display.
I’m thinking this is an issue on my email provider’s side where eM can’t connect to it? Or, not?
You didn’t say who the provider is.
You can set it up manually. Add a new account, but instead of the Automatic Setup, choose Mail > Other. Follow the wizard and enter the IMAP and SMTP details provided by your email provider.
If you are having issues with the security policies for your settings, use one of the following combinations:
SMTP
Port 587 = Force usage of SSL/TLS
Port 25 = Use SSL/TLS if available
Port 465 = Use SSL/TLS on special port (legacy)
IMAP
Port 993 = Use SSL/TLS on special port (legacy)
Port 143 = Use SSL/TLS if available
I attempted this previously…SMTP doesn’t show up to fill in. I tried again…still no luck.
When you setup a new account choosing Mail > Other, after entering your email address you choose IMAP and manually enter the IMAP server details.
The next screen is where to manually enter the SMTP (Outgoing server) details.
In the above screen the server would be something like smpt.whatevermail.com.
Thank you for your continued attempts to assist. I was able to get a SMTP tab by ignoring test results. Still can’t send emails. I’ve tried ports 587, 25, and 465…it reverts back to 587. 
Make sure you have the correct security policy for the port you have selected in your account settings. Often when you have the incorrect policy it will not accept your password.
If that does not help, please open a support ticket with eM Client. They will be able to assist you further.
go ahead and use manual settings and choose “other” for mail type. You can add SMTP there for version 7.2 and up