Status check - not everything is green. Website domains are being resolved externally.
Domain’s email is directed to this domain. [xxxxx.com ↦ 10 box.xxxx.com]
✓
Postmaster contact address exists as a mail alias. [postmaster@xxxxx.com ↦ administrator@box.xxxxx.com]
✓
Domain is not blacklisted by dbl.spamhaus.org.
I am having exactly the same problem. Everything was working fanstastically.
On a mac using both airmail and spark. Everything was great, but now all of a sudden none of the clients can send mails. Test SMTP throws a similar error in each case:
‘Stable connection cannot be established’
Using the webmail client is fine, but no other client will work.
I’m on a Linode, don’t see any custom firewall.
I checked UFW.
To Action From
22 ALLOW Anywhere
53 ALLOW Anywhere
25/tcp ALLOW Anywhere
587 ALLOW Anywhere
993 ALLOW Anywhere
995 ALLOW Anywhere
4190/tcp ALLOW Anywhere
80 ALLOW Anywhere
443 ALLOW Anywhere
22 (v6) ALLOW Anywhere (v6)
53 (v6) ALLOW Anywhere (v6)
25/tcp (v6) ALLOW Anywhere (v6)
587 (v6) ALLOW Anywhere (v6)
993 (v6) ALLOW Anywhere (v6)
995 (v6) ALLOW Anywhere (v6)
4190/tcp (v6) ALLOW Anywhere (v6)
80 (v6) ALLOW Anywhere (v6)
443 (v6) ALLOW Anywhere (v6)`
Where do I check Fail2Ban?