t-online.de does not show any emails, but gmail.com does.

t-online.de does not show any emails, but gmail.com does. Also, the ports and security settings for t-online.de are always forgotten after minutes, latest after a new start, and t-online.de cannot connect again. Funny enough: a very few t-online folders are showing content, but majority not. On the other side, no problems with my gmail.com account. 

Hi Alfred, what version of eM Client are you currently using? You mentioned some folders are showing emails, are you able to send/receive messages?

Are you using any firewall/antivirus with mail protection software on your computer? Can you make a screenshot of your account settings from Tools > Accounts > Your T-online account > IMAP/SMTP.

Thank you,
Paul.