Linux SSMTP Authorization failed (501 Could not decode user and password

Linux SSMTP Authorization failed (501 Could not decode user and password

I'm trying to send mail via ssmtp from a linux machine but get the following error:

Authorization failed (501 Could not decode user and password)

My ssmtp.conf is:
  1. root=mail@mydomain.com
  2. mailhub=smtp.zoho.com:465
  3. rewriteDomain=zoho.com
  4. UseTLS=Yes
  5. # Username/Password
  6. AuthUser=mail@mydomain.com
  7. AuthPass=********
  8. UseSTARTTLS=NO
  9. FromLineOverride=yes
My revaliases:
  1. user:mail@mydomain.com:smtp.zoho.com:465

What causes the error?