Inbox fails to synchronise (IMAP)

I’ve recently installed client 6.0.20320.0 to use with talktalk.net and IMAP.

The settings for IMAP are:

Login / Username  username@talktalk.net
Incoming mail server  mail.talktalk.net
Incoming Port   143
Outgoing mail server  smtp.talktalk.net
Outgoing Port   587
Outgoing SSL    No
Outgoing Authentication Yes

Folders synchronise with the exception of the Inbox which is empty (a web log in to the mail provider shows that it isn’t).

Within the log file I see:

17:16:49.727|012|   Exception:
17:16:49.727|012|     Protocol violation

Immediately after the first fetch.

Can I have some assistance to remedy this please?

Hi, can you please open eM Client and go to Tools > Accounts > Your talk talk account and make a screenshot of the account IMAP/SMTP settings?

Thank you,
Paul.

I’ve visited my neighbour and taken the screen shots (attached).

What was very odd was that when I started eM Client it correctly downloaded the emails - Inbox included.

When I sent an email from my phone this did not arrive - the send receive activity bar (bottom right) never completed.

When I shut down and restarted the client software the email appeared. 

The OS is Windows 8.1 (I forgot to mention that earlier).

If you provide an email address I will send the log files that I’ve captured during my visit (logging has been on since the initial problem).

Hi, I believe this is a server issue, can you please contact talktalk support in order to resolve the issue?
Let me know if you’ve managed to solve the issue…

Thank you,
Paul.