Hi all,



I wonder if anyone has come across this problem, and although I cite Outlook in the title, I'm not convinced it is related to Outlook although that is where it manifests!

All of a sudden I started getting send/receive errors on my Outlook 2013 (running on Windows 7 home premium). The error code is 0x800CCC0E, 'Unable to synchronise folders.....cannot connect to the server.'

This does not happen on all of the accounts (I have many on my Outlook) but only some. Normally with these IMAP accounts I use SSL/TLS, SPA secure authentication, so ports 993 and 25.

My Android phone can access the accounts without any problem using the above settings, as can my Windows 10 laptop running Windows 10 Mail. So the problem is specific to this computer.

Here is what I have found/done so far:

You can ping the mail server from the computer.

Initially, I set one of the problem accounts up in Thunderbird on the same PC and it did not work. I changed the account settings to use the non-secure connection, which the mail server supports, i.e. port 143 no encryption/password authentication and hey presto that worked!

So I tried the same non-secure settings in Outlook- turn off SPA authentication, select None for the encryption in Advanced, and again, the account now works. So whilst I have a workaround, the problem is that we don't seem to want to do secure settings any more. No coffee shops for me then!

• I then disabled the Windows firewall temporarily. No change.
• I turned off the AV protection. No change.
• I have a premium Malwarebytes Anti Malware subscription and I turned that off. No change (the PC scans clean with both the AV and MBAM btw).
• I went to Control Panel -> Mail and set up a new profile for Outlook, and configured one of the accounts under that profile with secure settings. It didn't work. Changed the account to use non-secure settings, and it did.

What else could I look at- could it be to do with SSL certificates or something like that?

Thanks for taking the time to read this.
Alan

Okay I managed to get just one of the accounts working with secure settings almost accidentally, by doing the following:

For the heck of it, I tried setting the 'Use encryption type...' to 'Auto' in More Settings -> Advanced, and I got a dialogue "The server you are connected to is using a security certificate that cannot be verified. The target principal name is incorrect"

So I viewed the certificate, whose status showed OK, and with an option to install it. So I went through that process, got a success message, OK'ed out of everything, and tried to set the account up with secure settings- and bingo, it worked!

My joy was short lived as none of the other accounts responded in the same way, and now I get the same certificate verify dialogue every time I start Outlook- although I can click 'Yes' to 'Continue using this server?' and the one account with secure settings still works.

The target principal name on the certificate is *.f-------s.net, which is OK for the server concerned which is within that domain. I am naming the server in the Outlook settings. Googling the certificate error does however suggest a mismatch in the settings- but everything appears correct, ports are correct- I'm using 993 IMAP and 465 SMTP for SSL/TLS.

In any case, such a mistake would not explain why it suddenly stopped working when my other devices and computers continue to work just fine?

I still think I'm on the right track with SSL and Certificates as the cause...

Alan