I’ve had 3 customers over the last 2 days reporting that they were suddenly unable to receive/send emails, I thought maybe it was a symptom of the recent issues with outages.
It seems that a mac update had changed their mac email account settings to use ssl for sending and receiving mail.
In all 3 cases unchecking the use ssl option solved the issue.
interesting update, thanks!
that in addition to about 3-4 other things have made some bad timing of issues all looking to be related but not exactly related together 
And another related to an antivirus update that decided to block windows mail
This is Windows, I presume. Window mail won’t open up in this case?
just pop3 and smtp ports were blocked by a v a s t on their pc
we just had the customer disable the mail shield and was all good again
Thanks for the info. May sure help us.
Looking further I think Avast is doing much more here. It silently redirects your email accounts to use encrypted channel, even when you set un-encrypted port in your email client software. If their software has this behavior, it must also do periodic checks if the port it self detected is available any more or not.
Quite a few POP3 client complaints we saw can be accounted to this behavior.
we also had another customer about a month back with a trial internet security product that had expired, once it expired it blocked the mail ports on their pc, can’t remeber which software package it was at the moment