nextnext1 for feature suggestions, yes. Not for support issues.
SMTP email doesn't work for me
jordanjay29 got it. going to open
5 years later
Just wanted to post a fix that worked for me 
In my case, I was using AWS for my email. AWS lets you use port 25, 587 or 2587. With port 25, I was getting this error:
flarum.ERROR: Swift_TransportException: Connection could not be established with host email-smtp.ap-southeast-2.amazonaws.com :stream_socket_client(): unable to connect to tcp://...............amazonaws.com:25 (Connection timed out) in /........./vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php:261Switching to port 587 fixed everything! Apparently my hosting provider was blocking low ports, which I guess kind of makes sense!
a year later
I have a similar situation.
It's 100% not the server. I have changed smpt-servers several times. Mail still doesn't work.
loopza
Hi, you should maybe check your server mail error log.
Also be sure on your hosting provider the port 25 and all necessary port for email sending are opened.
SMTP over SSL port 465 over TLS 587
For almost sure the issue you are facing is not from Flarum itself if you set SMTP authentication correctly.
I have everything set up 100%.
dkim, dmarc, mx records. Everything has been tested several times. Necessary ports are open.
SMTP is not working!
I had to choose the “mail” driver. So the letters come to the mail, but they go to spam.
loopza I had this issue before, and it took me a month to resolve. I thought you might be experiencing the same problem.
Are you using Cloudflare or another CDN? My issue was resolved when I disabled the proxy in Cloudflare. This might help you too.
Understand that SMTP is an outgoing protocol. CloudFlare has zero influence over where your server connects to in order to deliver email.
Make sure that encryption in your settings is lowercase. If it still doesn't work, share your configuration here (or via email if you have to) so we can double check.
PS. SMTP works fine in Flarum, it's a generic implementation and a generic protocol.
luceos I really don’t understand why you’re doing this. All I want to do is help people. Yes, if the SMTP server address is proxied by Cloudflare, email sending won’t work. I’m leaving many resources on the topic below.
I suggested that maybe the proxy might be active on the mail server in Cloudflare DNS settings, and the issue could be caused by this. I don’t think I said anything wrong.
luceos CloudFlare has zero influence over where your server connects to in order to deliver email.
You’re saying this just to contradict what I said, and yes, as you can see, if the mail server used in the SMTP settings is proxied, emails won’t be sent.
Unable to set up an email account hosted in Plesk in an email client when a domain is behind Cloudflare
This also means that any DNS record used to send email traffic must be DNS-only to bypass the Cloudflare network.
Cloudflare Developers - Dns / Email issues
i just click on Mail DNS and make cloud grey, now emails are working. Change your MAIL's proxy status to DNS Only ( grey cloud) and your email will start working
As I’ve said before, if the mail server used in Flarum’s mail settings is proxied by Cloudflare, email sending won’t work. I’m only pushing this because you specifically said, “Cloudflare has zero influence.”
It was just a simple suggestion. If you want no one else to reply to support topics, you can do that.
huseyinfiliz I did not intend this as a personal attack. I am grateful you're here to assist everyone with these problems.
What I probably should have asked for is, what does "SMTP is not working!" mean - do you see an error while using the test button for instance - and whether @loopza has checked their error log for any messages.
Once we know the error message, we can work our way back.
Again, my apologies if my message seemed to isolate you @huseyinfiliz , it wasn't.