Synchronizing folder failed

Hello! I’m so tired with getting this error. Can you please help me?

Sort of an answer.
I deleted my Outlook account from eM Client, than created a new one using manual settings (Tools - Accounts - New Account… - Mail - Outlook - …) and IMAP protocol instead of POP3. Works properly for 4 days :wink:

glad to hear switching to IMAP solved your issue.
Just as a heads up for future references, eM Client version 7 will set up microsoft mail accounts as IMAP or exchange manually, as the AirSync protocol is being discontinued for mail completely.