First synchronization stopped with the following error message

When
performing the first synchronization after the account setup, the process is stopped after synchronized about 200 emails, and gave the following error:
[email protected]: Connecting to [email protected] failed
[IMAP] An attempt to connect to [email protected] failed. This could be caused by temporary server unavailability or incorrect settings. Do you want to check the settings?

OS: Windows 10 64bit
eMClient version 7.2.33974.0

Can you upgrade to the latest version available at http://www.emclient.com/release-history and see if there is any difference. If it is still the same, disable your anti-virus and firewall and then try again.