Unable to send email from alias via Gmail

Unable to send email from alias via Gmail

I would like to use several email account aliases of my Zoho Mail account to send email via the Gmail email client. The strange thing is that I did manage to send email via Gmail from my main Zoho Mail account.

I tried to configure the send mail alias in Gmail with both the alias account name and my main account name. Both succeeded but when sending mail from the alias it never arrives at the destination. Also I received an mail on my Gmail address somewhere the next day:
  1. To: MyGmailAddress@gmail.com
  2. From: Mail Delivery Subsystem<mailer-daemon@googlemail.com>
  3. Body: An error occurred. Your message was not sent.

Please let me know how to solve this issue.

Here is some additional information on how I configured the account in Gmail.

  1. Port: 465
  2. SMTP Server: smtppro.zoho.eu
  3. Username: I tried both the alias and my main email account name (see 2nd paragraph)
  4. Password: I used a app specific password, generated at accounts.zoho.com
  5. Connection type: Secured connection using SSL