400535 5.0.0 Authentification Failed\n ;

400535 5.0.0 Authentification Failed\n ;

Hi, I synchronized my Zoho CRM email with my Outlook account, the verification succeeded and all contact emails synched. I am now trying to email a template and keep getting this error: 400535 5.0.0 Authentification Failed\n ;

What can I do to fix this?

Thanks!
Johanna