authenticationfailed message

I just bought a new computer and installed the emclient. Unfortunately always the error message authentification appears when the client is synchronising with the server. I tried several things like adding the account manually or importing it from my laptop. But the error message still appears. It’s also strange that when I test the settings of the account in the account diagnosis, IMAP and SMTP is ok. So i always receive the testmessage then. 

The only thing that is different to my laptop and my previous PC is, that I use Win10Home. The others are Win8.1Pro and Win10Pro. My actual version is 7.1.33101.0 (I use this version on my laptop where it’s working and on my new PC).

The most common cause of authentication errors, other than incorrect credentials, is when the settings are incorrect. You need to ensure you have the correct security policy. Go to Menu > Tools > Accounts, and check that you have the correct combination.

SMTP
Port 587 = Force usage of SSL/TLS
Port 25 = Use SSL/TLS if available
Port 465 = Use SSL/TLS on special port (legacy)

IMAP
Port 993 = Use SSL/TLS on special port (legacy)
Port 143 = Use SSL/TLS if available

POP3
Port 995 = Use SSL/TLS on special port (legacy)
Port 110 = Use SSL/TLS if available

The underlined ones are the best option for security if your server supports them. SMTP port 465 was reassigned and should no longer be used for SMTP, though many mail providers still recommend and use it.

Hi Gary

Thank you for your really fast reply. 

As I already described in my initial post - I exported the account settings from my old computer incl. passwords to my new one. It worked fine on the old one so incorrect settings can not be the reason. 

The diagnosis shows that my settings are correct and I can receive and send e-mails with the account but still get the error message every time the client is trying to connect to the e-mail server.