If you are setting up Outlook on a Windows 10 (and possibly Windows 8) system and get send errors when testing (even though all settings look correct) then try the following fix.
- Right click the start button (bottom left)
- Select Command Prompt (Administrator) – note it MUST be the Administrator option
- Type sfc /scannow and press Enter
- Wait for the sfc to complete
- Reboot your PC
- Try setting up the email account again
I’ve now seen this problem three times twice on a Win 10 system after upgrading and once on a Windows 8 system.
Posting this to try to save you the aggro that I went through trying to address this.