Outlook 2013 - Task 'xxx@mail.com' - sending reported error (0x800C8100): 'UnknownError 0x800C8100'

[NoGo]

Hi,

I am can receive incoming mails but unable to send outgoing mails. Previously working fine. No problem using mobile app or webmail on the same email account. Please help. Thank you.

 

[Emerald]

have you tried repairing or reinstalling Outlook?