As you know we have recently upgraded/migrated our cPanel Shared Hosting servers. In the old servers we had settings that allowing the plaintext authetication for emails, this was set as is originally to keep compatibility with email clients that doesn't has support for SSL/STARTTLS authentication.
Nowadays all the current email clients already support the secure authentication so for security reasons we will proceed to disable plaintext authetication in our cPanel Shared Hosting mailservers starting September 1st.
If you have an old software like Outlook 2007 or any other that doesn't support SSL/STARTTLS authentication, please upgrade to a newer version or software.
To keep the highest security in our systems the plaintext authentication for emails will be disabled on September 1st.
Starting September 1st our cPanel Shared Hosting servers will require clients to connect with SSL or issue the STARTTLS command before they are allowed to authenticate with the mail server.
If you have any question please open a support ticket.