Recently connecting to the SMTP server has got very slow and sometime it won’t connect at all.
From the mail log of the email client it appears the problem may lie with the time it takes to authenticate.
WROTE Jul 12 15:14:29.377 [kCFStreamSocketSecurityLevelTLSv1_2] – host:mail.server.co.uk – port:587 – socket:0x6000006a1b60 – thread:0x60400026c600
AUTH PLAIN (*** 72 bytes hidden ***)
READ Jul 12 15:15:49.663 [kCFStreamSocketSecurityLevelTLSv1_2] – host:mail.server.co.uk – port:587 – socket:0x6000006a1b60 – thread:0x60400026c600
235 2.7.0 Authentication successful
Also testing via MXToolBox the transaction time is slow.
However what I can’t understand is that this doesn’t happen all the time and no changes were made to Postfix configuration.
The amount of mail which is usually in the mail queue is tiny i.e. under 10
Any ideas what to look for / check etc I would be most grateful.