- Plesk Onyx 17.5 for Windows
Unable to send an email from one particular mailbox using Horde webmail (MailEnable is used as mail server):
PLESK_INFO: Error : there was error sending your message , server authentication denied
It's possible to send email from other mailboxes on the same domain.
Reset password for the mailbox:
Plesk > Domains > example.com > Email Addresses
and click on desired mailbox.